The guys at SlickEdit make a great set of tools for devs, both standalone and VS plugins. Scott Hackett wrote a really interesting post on using SlickEdit to do a code review. It's a pretty good read and shows a nice way to use the tools to help narrow down who wrote what code.
There are a number of ways to skin the code review cat; this is a nice option and worth the read.
(Reminder disclaimer: I got SlickEdit tools for free because they advertise on The Lounge. I wrote about my thoughts on SlickEdit in an earlier post.)