VMBear is an application very similar to VMWare. Currently it is in a very pre-alpha stage, although it is not known to be terribly buggy. Since it does involve a kernel module which does some pretty odd things, I certainly would not suggest running it on any system you care about. Currently most of my testing is done inside of QEMU.
The most recent version can be retrieved from anonymous CVS on the project page.
Papers:Here is the most recent screen-shot.
