iOS 6 brings load of fun like Siri updated, flyover, don't disturb feature and so on. Report saying the firmware contains up to 200 new features for those who upgraded once it's publicly released. However if you are not a developer, you still can download it.
Download iOS 6 Beta 1 For iPhone, iPad & iPod touch
Therefore Apple doesn't want to take a risk to release iOS 6 beta 1 for public release, but for developers only. But once they get their hands done fixing the bugs, they will release it from its cage.
However, as I mentioned on the first paragraph that you can download the firmware to find out what exactly Apple is offering this time and dive deep into its stomach to search something interesting.
Please read this before going! iOS 6 is in early stage as we know the software is beta now, means buggy and errors could be all over the place. There is no untethered jailbreak yet and you will lose your unlock ability too once installed iOS 6 without UDID (developer account). Proceed at your own risk. But don't worry you can downgrade to iOS 5.1.1 firmware at anytime
Anyway these are the download links based own your existing devices:
- Download iOS 6 beta 1 iPhone 3GS
- Download iOS 6 beta 1 iPhone 4 GSM
- Download iOS 6 beta 1 iPhone 4S
- Download iOS 6 beta 1 New iPad 3 Wifi
- Download iOS 6 beta 1 iPad 2 Wifi+3G
- Download iOS 6 beta 1 iPod touch 4