You can use CodeBlocks with gcc. Its free. If you don't mind the resulting pigsty, you can use QT Designer with gcc. It is also free. It is intended for QT projects only, but you can coerce it for other types of development, especially for personal training. Since you don't come from the *nix side of things, QT Designer would probably be the friendliest freely available IDE out there.
The gcc port CodeBlocks uses is called MinGW, you can also use it directly or with an IDE other than CodeBlocks (but there's nothing wrong with codeblocks)