The Beta version of Ubuntu Linux 9.04 is out.
I don't recommend the beta release for anything you want to keep working and stable, but if you want to run the liveCD and get a preview of what's coming at the end of April it's here.
9.04 promises faster boot up and support for the new Linux file system ext4. It also provides the really ambitious folks the tools to build a cloud computing server system.
This may be an interesting year for Linux. Cloud computing is hot and with all the little mini laptops on the market (perfect clients for cloud computing clusters) I imagine it'll get hotter. Ubuntu is packaging the tools for the server guys to use into it's system... It's only a matter of time I think before cloud services start popping up in large numbers.