The Ubuntu 10.04 “Lucid Lynx” Beta 1 is released on 19 March 2010 and available for download.
In addition to their six-monthly stable releases and our daily development builds, they also make regular testing releases during the development cycle. With just a few spare minutes, you can provide valuable feedback on a test release and help polish and stabilise. Please see the testing wiki page for more information on how to test and report back. Links to the test release downloads can be found on the pages listed below.
Please test the latest available edition. Thank you!
More info here
http://releases.ubuntu.com/releases/10.04/ (Ubuntu Desktop and Server)
http://uec-images.ubuntu.com/releases/10.04/beta-1/ (Ubuntu Server for UEC and EC2)
http://releases.ubuntu.com/kubuntu/releases/10.04/ (Kubuntu Desktop and Netbook Remix)
http://cdimage.ubuntu.com/ubuntustudio/releases/lucid/beta-1/ (Ubuntu Studio)
Enjoy your testing!!