JCR is a Web application for performing and managing formal code reviews. Although it has some special logic for reviewing Java projects, it can be used for reviews of any type of source code. JCR manages all stages of the review process (initial project setup, individual review, joint review meeting, post-review tidy-up), but it's mainly there to show diff views of files that have changed and to allow comments to be made on any line of any file marked for review.
This release candidate contains a number of functional enhancements. The most important are improved generation of file diffs, display of intra-line diffs in files, keyboard navigation support when reviewing, and display of modification stats (lines, diff chunks, and percentage change) for each file. The keyboard navigation in particular speeds the review process up markedly. There have been many other more minor enhancements, plus a number of bugfixes.
URL: JCR - Java Code Reviewer