IBM provide complete end-to-end Linux Support. They support all major Linux based Operating Systems including Red Hat and SUSE on all hardware platforms. Linux is a key component of IBM's future vision and current reality of "On demand Infrastructure Services" They also certify and support all of their own software on Linux.
http://www.ibm.com/news/au/2004/04/2004043001.html
http://www.ibm.com/linux