Get on the net and do a search for the Kelly or Edmunds new car guides. I think it's a must before purchasing a new car as they give you all the details of what your looking for as well as the dealer's cost. Negotiate from that price. Lots of tips on what to do and what not to do when negotiating.
I believe Consumer Reports will also send you a comprehensive report of a particular car you're interested in but there is a cost (somewhere around $12.95 or so).
Good luck.