Apple is rounding out the week with a treat for developers, releasing the latest beta 4 of iOS 5, along with a new beta of iTunes.
One of the big new features to show in beta 4 is the ability for iOS updates to be installed OTA, no PC required. For now, at least, that ability comes with a pretty big caveat, with Apple noting that you'll need to re-sync your photos afterward, with them disappearing during the update.
There are a ton of little changes in this new release, so you'll want to check out the full changelog for a complete run-down. Some of those you'll note include enhanced AirPlay video support, an updated WebKit engine, and support for wireless iTunes sync on PCs.
Some users have run into problems upgrading from a previous beta to beta 4. In those cases, backtracking to iOS 4 before installing the update seems to work in some cases.
Of course, there's no jailbreak available yet for iOS 5 beta 4, but it really is just a matter of time now.