Following the successful post-WordCamp San Francisco code sprint, we are now ready to release the second beta of WordPress 3.0.
Things to test:
- Revised menu user interface
- Changes to the WordPress exporter and importer to make it more flexible
Already have a test install that you want to switch over to the beta? Try the beta tester plugin.
Testers, don’t forget to use the wp-testers mailing list to discuss bugs you encounter.
We hope you like it! And if you don’t, well, check back when the release candidate is ready. 
Download the WordPress 3.0 Beta 2 now!
Read more: http://wordpress.org/development/2010/05/wordpress-3-0-beta-2/