If you are new to investing and want to learn, I suggest the LA Times Investor 101 website:
Money Library - Los Angeles Times
If you just want a quick and easy investment I would consider a Target Date Retirement Fund from Fidelity, Vanguard, or T Rowe Price. These are basically "funds of funds", where you can buy one investment which is actually a basket of funds, which adjusts to more and more conservative investments as you age.