This is a tip on how to find external plug-ins:
After download you can import them into your project via File -> Import
After that you have a new binary plug-in in your workspace which you can also put under version control and share with your collegues.
Note: You may have to remove the filter on binary project in your package explorer.
Here is the Jersey reference implementation website
Very good description on how to use Google Code with Mylyn can be found here:
http://eclipse.dzone.com/articles/using-mylyn-with-google-code-u
I receive regulary questions about my website and the posted articles. As some of these questions repeat themself I decided to try out a more open discussion forum. Therefore I created the following google group:
http://groups.google.de/group/vogella
Please use this group if you have question which relates to my articles.
This article one looks nice: