Bug Tracking for Windows and SVN

Question

I'm working as part of a volunatry team creating an open source product with a permissive license. We are currently using Visual SVN Server/TortoiseSVN for source control and TeamCity for our continuous integration builds.

I would like to add a bug tracking component into the mix that will integrate into SVN. Ideally, I'd like to use FogBugz but we have no budget. So, I need an alternative. The requirements are:

• Must be free or have a free version supporting at least 20 developers (we're volunteers!)
• Must integrate with VisualSVN Server
• Must run on Windows
• I prefer Microsoft technology (ASP.Net over PHP; SQL Server over MySQL, etc) because we are a Microsoft shop, we have experience with those tools and already have them installed.
• Must be able to work with a geographically distributed team
• Must work with Express editions of Visual Studio (the developers don't all have the Pro version so we can't rely on Visual Studio add-ins).

I'd like The Community's recommendations, please, for products that meet all of the above requirements.

[Clarification: our license is very close (though not word-for-word) to the MIT license.]

Answer 1

JIRA is free for open source projects and will run on Windows. Subversion integration is available and provided through a plugin.