WordPress had released its latest version 2.3 beta and it’s now available for download and testing. For BETA tester be sure to report any found bugs and any loophole to WordPress staff for better security in the future.
Beta 3, the third and final beta for WordPress 2.3, is now available. Many bugs have been fixed since the second beta, and we could use your help finding and fixing more bugs in preparation for the first Release Candidate due next Monday. The standard disclaimer for betas applies. Beta 3 is pre-release software that is still being tested.
Quoted from WordPress beta download form, you can view more details and download the BETA here