Apple has just released iOS 5 beta 3 (9A5259f) for iPhone, iPad, iPod touch, and Apple TV, along with iTunes 10.5 beta 3 for Mac, and Xcode 4.3 Preview 3 for developers.
While in previous years Apple had stuck fairly closely to an every-second-Tuesday beta release schedule, iOS 5 beta 2 hit on a Friday just over two weeks after beta 1, and now beta 3 is on a Monday just under 2 weeks after beta 2. On average, the pacing remains similar, however, and Apple has previously said the release version would come this fall. (Likely September/October to coincide with iPhone 5 and perhaps other new devices.)
Interestingly, they're once again doing a traditional, tethered release. No signs of them testing the bit-differential/delta file update system yet.
If you're a paid, registered developer with Apple, go get it. What if any changes have been made in iOS 5... we'll have to wait and see. As always, we have comments below and a special iOS 5 Forum for your discussion pleasure.
(Reminder: if you're not a paid developer, stay away. Buying slots can get you scammed, and running beta software on your main device can leave you stranded. Wait for fall.)