Apple just released the fourth beta version of iOS 5 which brings with it and a new way to upgrade namely OTA (Over the Air). Unfortunately there are already users who say that the upgrade via wireless doesn’t work as it should.
Luckily, the developers and people familiar with this procedure can download the software manually using a channel intended for developers offered by Apple. iOS beta 4 is available for owners of iPhone 3GS, both variants of iPhone 4, all versions of the iPad and iPod touch generation of the third and fourth.
For a successful synchronization, you need iTunes 10.5 Beta 4, also available in the new channel for developers at Apple, along with a new Xcode 4.2 Developer Preview 4. With iTunes WiFi synchronization is supported on PCs with Windows. Note however that in order to upgrade the iOS you need 5 beta 3 is already installed and then switching to iOS 5 beta 4.