TortoiseSVN The coolest Interface to (Sub)Version Control

TortoiseSVN 1.5 allows using plug-ins for specific issue trackers.

They're implemented as COM-objects using the IBugTraqProvider interface and allow for example to show a list of open issues directly from the commit dialog.

Gurtle is the first open-source plug-in available, which integrates TortoiseSVN with the issue tracker for projects hosted at Google Code.

If you have a project hosted there, you should give Gurtle a try. Even though its version number is at the time of this writing 'only' at 0.2, it's already stable enough for everyone to use.