A version of the RadioKit SDK is now available with support for XCode 4.5 and iOS 6. If you already have an app using RadioKit and are just looking for the library so you can target the new iPhone 5, the library can be found here:
http://stormyprods.com/Libs/RadioKitLib-XCode4.5.zip
If you would like a full XCode 4.5, iOS 6 demo project, it can be found here:
http://stormyprods.com/Demos/RadioKitARC-4.5-Demo.zip
Full details about the RadioKit SDK can be found here:
http://www.stormyprods.com/products/radiokit.php
Please note: with XCode 4.5, Apple has removed support for armv6 and will only allow builds targeting iOS 4.3 and higher. So, if you still have projects targeting armv6, or want to use XCode 4.4 or lower, you will want to use the older RadioKit library.
Also note that existing apps already using an earlier version of RadioKit will work just fine under iOS 6 as-is. You only need to get this new update if you specifically want to build an app using RadioKit and XCode 4.5.