... You might want to 'test' for how much moisture you may or may not have.
Here are a few recent posts that talk about finishing a basement, moisture control, and moister 'testing'. So, a couple directly answer your question and the others, well, they address finishing a basement.
There an article in a recent copy of Fine Home Building that talks about finishing a basement. The interesting thing about it is it talks about NOT using a vapor barrier. I would like to add that in many parts of the country, vapor barriers are used, and are used for a variety of different reasons. Those reasons range from "I always finish basements off using a vapor barrier" to "It protects against potential moisture." So, shoot, er, suit yourself. (Just jesting.)
Good luck! If you have any more questions, post them up. My best to ya and hope this helps.