Cobertura has an Eclipse plugin, but it's suffering from neglect. So I'm putting a small bounty on it. $250 to the person who gets it back up and running.
My requirements for the plugin?
-Runs Cobertura from within Eclipse
-Highlights your tested and untested source code
-It'd have to run to one of the core committer's satisfaction. When they're happy, I'll mail you a check. It's not a ton of money, but it's a few dollars.
There you go... there's a file in the build (eclipse-plugin.zip) that'd make a fine starting point.
Given that so many people at are Java One this week, it might be a bad time to announce this... on the other hand, with so many people busy, it might be ~your~ chance to get a head start. :)