You can use ReviewBoard (http://www.reviewboard.org, free, os)
It works great because it allows you (and your fellow team members) to go through the review process just with some clicks in a centralized web system. Of course, this requires a minimal setup in a server, but this payoffs if you consider that you won't need any client installation.
How it works: basically,
- You commit your work in branch,
- You create a review request,
- Any peer can browse the tool, select any review, and he will automatically see the diff.
- Finally, he can write inline comments and return it to the author.
.. as you see, no need to download or unzip anything. The tool will connect to your SCM system and visually display the diff.
It support other workflows, too.. you can browse the docs and the live demo to see if it is a good fit for you.
I highly recommended it.