The mantra of investors used to be an either-or proposition: Save your money or save the trees. With recycling and going-green costs skyrocketing in the '90s, most people simply gave up expecting a decent return on their environmentally friendly investing practices. But times have changed.

Now, many corporations have discovered efficient ways to introduce socially responsible initiatives in their daily operations. Whether the moves are geared toward improving the environment, helping alleviate poverty, or enhancing educational opportunities, plenty of companies now offer opportunities for investors to help make the world a better place.

The market for the green arena specifically has never been brighter. There are mutual funds geared toward Earth-friendly investing, established retailers such as Starbucks (NASDAQ:SBUX) and Whole Foods (NASDAQ:WFMI) who pride themselves on their earthy innovations, and a whole cadre of companies such as Suntech Power (NYSE:STP) and Pacific Ethanol (NASDAQ:PEIX) that have made it their mission to contribute to creating profitable sources of alternative energy.

More consumers are beginning to show an affinity for understanding and protecting our environment. It could be only a matter of time before all companies align themselves with greener policies or risk losing investor confidence and interest.

The message in Al Gore's An Inconvenient Truth and this year's popular Planet Earth TV series visually demonstrate the harmful changes in the environment. While not all scientists agree about the extent of our role in causing these changes, the popularity of the documentary led Gore -- alongside a handful of other public figures -- and Microsoft's MSN Network to launch a seven-continent concert series with a lineup of more than 100 music heavy-hitters to engage more than 2 billion people. The campaign for awareness even stems into the virtual world -- David de Rothschild of Adventure Ecology flooded several virtual cities in Second Life to illustrate what would happen as a result of global warming -- in this demonstration, many avatars were temporarily displaced.

Luckily, it's possible to make green from green, so to speak. To highlight how investors can participate in and profit from this growing phenomenon, The Motley Fool is running a series in advance of Earth Day on April 22. We'll explore Coca-Cola (NYSE:KO) and its recycling campaigns, General Electric's (NYSE:GE) Ecomagination cornerstones, Disney's (NYSE:DIS) environmental policies, and many other corporations with practices that we as shareholders can both applaud and profit from. So check out our listing of articles below, and celebrate Earth Day this year by thinking green for your portfolio as well as for the planet.

Starbucks, Whole Foods, and Disney are Motley Fool Stock Advisor selections. Coca-Cola and Microsoft are Inside Value recommendations, and Suntech Power is a Rule Breakers pick. All of our investing newsletter services offer a free, 30-day trial.

Shruti Basavaraj owns shares of Disney. Katrina Chan does not own shares of any company mentioned above. The Motley Fool's disclosure policy is eco- and investor-friendly.