From the official press release on the Ubuntu site:
"The Ubuntu team is proud to announce the release of Ubuntu 6.06 LTS server for Sun SPARC 64-bit architecture. Highlights of this release include: new kernels targeted at server platforms, the server kernels are tuned differently than the desktop kernels (providing better performance for server applications); turn-key LAMP installation for this common deployment scenario; improved support for clusters and SANs."
Cool. I am proud to be part of this wonderful distro. Now that 4 CPU architechtures are logged under the belt, I can only think of two of other Linux distros that have more- Debian with 12 and Gentoo with 8. Why is this cool? Accessibility. It's all about corporations having the ability to be able to move to a distro that supports their CPU. And with Ubuntu having commercial backing and support, this could be very tempting for said corporations.
At any rate, congrats to the Ubuntu team for what I think is a fairly large move. Now if only I can find some confirmation to the rumors of the Ubuntu + Sun Microsystems marriage...