Free I don't really know any from personal experience. I do know microsoft has a 1 year trial for thier C++ 2005 express edition.

However, free this is what I have come up with. There may be more and/or better and I have no personal experience with it. Give it a try if you want.

http://www.bloodshed.net/dev/devcpp.html

Also this may interest you...

http://www.digitalmars.com/

I have no experience with either. I have just been using the Microsoft Express Editions for my college classes since that is what the class assumes you are using(no teacher support if any other compilier doesn't do what the book says it should do).