One of the most popular Linux companies and distros around has recently partnered with VMware. Red Hat Linux will now be coupled with a second virtualization product, the first of which is XenSource, which will be included in RHEL 5. While the deal between the two companies doesn't focus around money, it does give VMWare a leg up on one of their competitors, XenSource. They plan to further integrate themselves in the future:

Down the road, Red Hat and VMware look to ship "channel bundles" that pair Red Hat's Linux and Application Stack with VMware Infrastructure - VMware's own application stack - and VMware Server. The companies have also pledged to back each other up in debates around how future versions of Linux should handle virtualization.
The innate value of virtualization makes it a hot topic for any sys admin or system planner, and since Red Hat has had a tough time recently, losing share to many other companies, this is a good way for them to strike back.