Given that OS 4 beta 2 was buggy, caused issues with the camera (to the point that it froze and stopped working altogether), and killed the ability for screenshots, I'm very happy to see OS 4 beta 3. No really - I'm very, very happy. No word just yet on any improvements/changes/bug fixes in the new beta, but I'll be sure to keep you updated as soon as mine finishes installing. If you subscribe to the Apple iPhone Developer Program, head on over to get your OS 4 beta 3 fix, and report back with your findings (at your own risk, of course)!
Update: Looks like Apple has pulled the update down. We'll be sure to keep you updated as we hear more!