Extremely handy cvs faq. If you've never used cvs before, it's a way of storing code/documents so it's automatically versioned, archived, and you can have different development branches (cvs homepage). I can sum this up in two pieces of advice:
Once you start using cvs you'll never want to go back.
Fucking branches. Fucking merging. Files in the Attic? Wtf? Trunkshafted. Arg!