Of all the changes in recent years that have increased the amount of information available to individual investors, the opening of company conference calls to the public is one of the most significant. Together with SEC filings and the plethora of information available on most company websites, conference calls are a critical investing resource. If you're an individual investor and are not listening to the occasional conference call, particularly for a company whose shares you own, then you're missing out.

Company conference calls usually occur in conjunction with quarterly earnings releases, and provide corporate executives an opportunity to explain their results and business strategies to Wall Street analysts. Once off-limits to individual investors, most are now publicly available and any investor can listen in. It's easier than ever to do so: investors can access many company calls at The Motley Fool, through the Conference Call Calendar on our Quotes & Data page. You can also access conference calls -- either live or as a replay -- through a company's website. For investors who prefer the phone, some companies will provide an 800 number for replays.

OK, so it may be easy to listen in, but why should you? What will you get out of these calls? What follows are eight items investors should listen for.

1) Quarterly results. Most conference calls begin with the boilerplate numbers that you can also find in press releases, such as the company's sales, earnings, and earnings per share (EPS). Nevertheless, even these opening minutes will usually include details not always found in the press release, such as operating margins and other figures. As a result, even if you're hearing stuff you've already read, stay attentive for the extra details.

2) Financial details. The basic quarterly numbers are usually followed by a more detailed discussion from the company's Chief Financial Officer (CFO). Even if a company includes a balance sheet in its earnings press release, more detailed metrics such as days sales outstanding (DSO) are usually only discussed in a conference call. DSOs are an indication of how a company is handling its accounts receivable, and many companies will also give a target for DSOs, and discuss other balance sheet items, such as inventory.

For example, in Nortel Networks'(NYSE: NT) most recent conference call the company discussed targets for both inventories and accounts receivable, and addressed why inventories were higher than the targeted level. A company may certainly engage in "spin" here, but the added detail is nevertheless helpful.

3) Sales details. Many companies will provide additional information about their product sales in conference calls. This can be particularly relevant as a company rolls out new products. Does the company have a sales target for its new product(s)? If a product has been in the market for some time, is it meeting targets previously set? Listening to conference calls over time can be particularly valuable in these cases, as companies may not always remind listeners of what they said last time, particularly if they don't hit previously stated targets. Other sales details include regional numbers, which are important to monitor as a company expands internationally.

4) Customers. If you're not sure who is actually buying your company's products or services, a conference call can be the place to find out. Even if you have a general idea, it's worth listening for new contracts and customers the company has gained.

This is obviously a little different for retailers and mass-consumer product companies, who have thousands, if not millions, of customers. But for corporations selling big-ticket items, this can be key. For example, many newer telecom equipment companies discuss "10% customers" on their conference calls, meaning customers that account for 10% or more of their revenues. Since investors are usually looking for as broad a customer base as possible, the fewer 10% customers the better, since a larger base dilutes the revenue from any one customer. Information about new and existing customers is usually one of the central points of discussion in conference calls for companies like Sycamore Networks(Nasdaq: SCMR), Corvis(Nasdaq: CORV) and other newer networking equipment companies. For a company such as Yahoo!(Nasdaq: YHOO), there is a similar focus on its advertising customers.

5) Future projections. Most conference calls also include some estimates by the company regarding future sales and earnings growth. Certainly spin and a company's innate optimism are a factor here as well, but where do you think Wall Street analysts get the information they need to formulate their own earnings estimates? An honest company is likely to be the best source of information about its future sales and earnings, and investors should take the opportunity to get this information straight from the horse's mouth.

6) Analyst questions. As much as The Motley Fool likes to poke fun at Wall Street analysts, and in many cases deservedly so, on balance the questions analysts ask on quarterly conference calls are helpful, and are what keep the calls from simply devolving into corporate PR and hype. Company executives are aware that they are speaking to a group that is generally very knowledgeable about their company, their business, and the results they're expected to announce.

Just as one example, last August questions were raised on an ADC Telecommunications(Nasdaq: ADCT) conference call about the health of smaller, upstart local phone companies known as competitive local exchange carriers (CLECs), and whether their difficulties would affect ADC's telecom equipment business. While company executives brushed aside any concerns, this was an early indicator: A couple of months later, the health of CLECs and concerns over carrier capital spending were the only things anyone was talking about.

However, analyst questions are not always useful, of course. If you hear an analyst inquire about a seemingly random part of the income statement, for example, it's usually just so he or she can fill out an earnings model that will be used to formulate a "target price," something that you, as an individual investor, can be happy that you don't have to worry about.

7) Jargon. There's no way around it: conference calls are usually dry, formal events, if not outright boring at times, despite the useful information they provide. One way to counteract the tedium is to listen for, and be amused by, the jargon and verbal tics that company executives and analysts invariably use. A few favorites of ours here at the Fool are:

Color and granularity: On conference calls, these terms do not refer to sand or the quality of a diamond. Instead, they are analyst-speak for greater detail, as in: "Can I get a little more color on your international sales?"

"Great quarter, guys": Many analysts preface their questions with this phrase, which is really just a polite way of saying hello. Of course, it doesn't necessarily mean that the company actually had a great quarter.

Visibility: This is a buzzword that does actually mean something. Visibility refers to how reliably a company can estimate its future revenue and earnings. A company with an order backlog, for example, can provide a more accurate estimate of their future business and therefore greater "visibility" of future earnings.

8) CEO Personalities. Another dynamic that can enliven many conference calls is the personality of the CEO. Other than attending an annual meeting, which few investors can do, listening to a company's executives presenting quarterly results can be the best way for investors to get at least some feel for the people in management.

For example, anyone listening to WorldCom (Nasdaq: WCOM) CEO Bernie Ebbers' stentorian, strict delivery during that company's conference calls is not in any doubt about who's in charge. And when Oracle CEO -- and world's second-richest man -- Larry Ellison was asked about Oracle competitor PeopleSoft(Nasdaq: PSFT) in the company's September conference call last year, he replied with typical Ellison bravado: "We don't see PeopleSoft at all -- except in ads in The Wall Street Journal."

Get comfortable
Conference calls may seem intimidating and impenetrable at first, but once you're comfortable with some basic financial terms, and with the company giving the call, they can be an invaluable resource. And if you don't understand something on the call, or you have notes you'd like to share with your fellow investors, then be sure to visit the Fool's discussion boards, and take advantage of another excellent investing resource.

Chris Rugaber does not own shares in any company mentioned in this article. His stock holdings can be seen online , as can the Fool's disclosure policy .