Apple has released the iOS 6 GM Seed to developers on the iOS Dev Center. No info yet on wether or not there will be an OTA update.
The build number is 10A403 and it is available for the following devices:
● iPad Wi-Fi (3rd generation)
● iPad Wi-Fi + Cellular (model for ATT)
● iPad Wi-Fi + Cellular (model for Verizon)
● iPad 2 Wi-Fi (Rev A)
● iPad 2 Wi-Fi
● iPad 2 Wi-Fi + 3G (GSM)
● iPad 2 Wi-Fi + 3G (CDMA)
● iPhone 4S
● iPhone 4 (GSM)
● iPhone 4 (CDMA)
● iPhone 3GS
● iPod touch (4th generation)
If you are a developer then you can download it from here.