The exciting world of mortgages offers much more than just your standard 30-year or 15-year loans. There are such beasts as 40-year fixed-rate mortgages, for example. These have been around for a long time but are now on the verge of becoming more widespread.

Fannie Mae (NYSE:FNM) has been working with 22 credit unions to develop 40-year fixed-rate mortgages. If these do well, we can expect other major lenders such as Bank of America (NYSE:BAC), Wells Fargo (NYSE:WFC), E*Trade (NYSE:ET), J.P.Morgan Chase (NYSE:JPM), Citibank (NYSE:C), and Wachovia (NYSE:WB) to follow suit.

With these loans, the interest rates are higher. (Boo!) But the payments are lower. (Yay!) (They're often not that much lower, though, so you may not want to opt for this loan if you can swing a 30-year one.) You'll pay much more in interest over the life of the loan on a 40-year mortgage than you will on a 30-year one. (Boo!) The new loans can be a bit easier to qualify for (Yay!), and the maximum amount one can borrow is often higher. (Yay... sort of.)

These loans, by offering lower payments, can make home-buying possible for those who otherwise wouldn't be able to afford it. That sure seems like a good thing, but there's also merit in the thinking that some people buying homes today shouldn't be doing so, since they're on shaky ground financially. If they can't keep up their payments, they'll lose their homes. Similarly, being able to take out larger mortgages means more people will be boosting their debt levels -- not always a great thing.

Interested homebuyers can often find better deals than those offered by 40-year fixed mortgages. Consider, for example, adjustable-rate mortgages (ARMs). They can be ideal for those who know that they'll be in their new home only a few years, as ARMs can lock in low rates for the first few years before beginning to permit controlled increases in the rate. Additionally, ARMs typically offer lower rates than fixed-rate mortgages. With ARMs, you may be able to build more equity in your home in a few years than you would with a 40-year loan.

Learn more about mortgages in these articles:

Learn more about buying, selling, and maintaining a home in our Home Center, which also features special mortgage rates. Also, visit our Buying or Selling a Home and Building/Maintaining a Home discussion boards to get some great insights and tips from fellow Fools.

Longtime Fool contributor Selena Maranjian does not own shares of any companies mentioned in this article.