You mean like this?

http://support.apple.com/kb/DL840

Installed and worked fine for me on Windows 7 without compatibility mode or anything, and didn't require a disc. It did install Bonjour in the background, so it looks like it's required for configuration, but not any of the other features of the Airport.

Older versions also exist going back to 2003:
http://support.apple.com/kb/DL537
http://docs.info.apple.com/article.html?artnum=120273