I recommend putting in the maximum amount that your company will match. It depends on how your company’s plan is set up, but here we get 50% of our contributions up to 6% of our salary. If you think about it, you’re getting an automatic 50% gain on your earnings and no fund manager can beat those kind of returns.
As for the individual funds, there should be some sort of guide that you can read about the different options your company offers.
I went with an Index fund for my 401(k) because fund managers are all a bunch of crocked, greedy bastards.
This is a pretty good site for basic information in laymen’s terms:
http://www.fool.com.
I stay away from their investment “advice”. These guys garnished a reputation for working miracles back in the 90’s and truth is, a blind monkey with a dart could pick a winner in the 90’s. They do a really good job of breaking things down so that you can understand them.