On March 26 Ubuntu 9.04 Beta was released. I installed it on my main desktop system as soon as it was available, so I’ve been running it for a few days now. More here
If you’re interested in trying out this beta release, remember that it’s intended for testing and not mission-critical systems. The release candidate is coming on April 16, and the final on April 23. Use the Bittorrent downloads to get your disk ISO the fastest!