I use the SWT Browser control in my Eclipse RCP application. On Linux Ubuntu 10.10 this depends on the user having installed xulrunner-1.9.2. This works fine.
For Natty, check out this page: http://www.maplef.net/blog/archives/ubuntu-upgrade-eclipse3-5-to-3-6.html (ignore japanses/chinese stuff, just follow the code to reach shangri-la)