The page you are currently viewing is the Classic InvestorGuide. The new InvestorGuide is more detailed and has more content and links than you can find here. If you have an older browser or prefer this pared-down, simplified version of the site, use the links in the orange column to navigate, and you can use this link to reach the Classic homepage . 22 million people are doing it, and you probably should be too.
Most companies allow only one fund family, and a couple of funds within the family.
It's like free money. Don't put too much of it in your company's stock - you're already very dependent on the company for your job. Remember that you will be heavily penalized if you withdraw your money from the plan before turning 59.5, so don't contribute money you might need anytime soon. A great place to start. A Disaster in the Making Worth article.