Codestriker is an open-sourced web application which supports online code reviewing. Traditional document reviews are supported, as well as reviewing diffs generated by an SCM (Source Code Management) system and plain unidiff patches.
There are integration points with CVS, Subversion, Clearcase, Perforce, Visual SourceSafe and Bugzilla. There is a plug-in architecture for supporting other SCMs and issue tracking systems.
Using Codestriker for your reviews minimizes paper work, ensures that issues, comments and decisions are recorded in a database, and provides a comfortable workspace for actually performing code inspections.
An optional highly-configurable metrics subsystem allows you to record code inspection metrics as a part of your process.