Most developers these days use a version control system to keep track of changes in their code, and Subversion is probably the most popular. While there are some slick Mac clients available, some folks have wanted a solution that integrates with the Finder like the Windows client TortoiseSVN integrates with the Windows shell and the SCPlugin brings exactly that. While they still have some features on the wish list (e.g. repository browsing), the developers think the newly released version 0.7 is "ready to be your one-and-only Subversion interface." It offers contextual menu control for common operations as well as icon badging to help you see file status visually.
SCPlugin is open source and a free download from Tigris.org
Update: I hear ya. I didn't realize at first that Versions is a no show so far. So all the more reason to check out SCPlugin!