Scott Bellware brought up SmartBear Code Collaborator code review tool as a way to annotate code on the ALT.NET mailing list today.  It looks really interesting to me since my entire team works remotely and facilitating code review is pretty difficult.  We've used NetMeeting in the past, but I would like something that promotes a more organic code review which naturally happens when co-located.

The really neat thing is that integrates tightly with source control systems such as Perforce's Windows client so that you can initiate a code review of a particular changelist before checkin.  I didn't see any mention about SVN integration...