WordPress 3.1 is running just a little bit behind schedule. The second beta was released ten days ago and more testers are needed to make sure that the final release doesn’t ship with any undiscovered bugs.
The final release is hopefully not too far away, so now’s the perfect time to download the beta and make sure that your plugins and themes work. If you find any bugs with WordPress 3.1, please feel free to discuss them with the wp-testers mailing list.
Have you tried WordPress 3.1 yet?