The only free and usable plugin: Jupiter
Update-Site: http://csdl.ics.hawaii.edu/Tools/Jupiter/Download
Works good, adds marks/comments in the editor.
Drawback:
Comments are saved as XML in a folder, which must be shared with all other developers (SVN(each comment = new Revision) /Samba)
Conclusion:
Make 1 review on 1 checked out source and commit OR create a samba server and link it to the review-data-folder, so reviews can be shared without commits.