The cvs manual and man page is already cited above at the very beginning. Another CVS tutorial can be found here:
It is very good for basic commands, not so good on setting up shared project directories.
You can find more online resources via google.
Finally, if you are desperate you can try to get help directly from me via rgb at phy.duke.edu. Remember, though, that I already wrote this whole tutorial, and have lots to do. So try to spend your own time instead of mine first (unless, of course, we are working together on a project and you are reading this document to prepare for that).