BugTracker.NET is a web-based bug tracking system that has git integration. The web pages for the git integration look pretty much like the ones for the subversion integration, documented here.
You can read more about the philosophy that guided BugTracker.NET/Git integration in this Stackoverflow question: How does bug tracker/version control integration work with typical git workflows?
See also this question:
https://stackoverflow.com/questions/229303/are-there-any-good-issue-tracking-systems-that-can-track-git-commits-branches
