I'm pleased to announce that we released Unity iPhone 1.5.1 yesterday. Unity iPhone 1.5.1 includes improved XCode support and improved AssetBundle support, but more importantly Native APIs (NSGetEnviron and exc_server functions) have been removed to comply with new Apple requirements, previously reported by Joachim here.
This release also removes the requirement for prospective users to write to our sales staff for an *evaluation copy, you can now just go directly to our download page to try it out for yourself!
For more details about Unity iPhone 1.5.1, please check out the release notes.
*Note: Unity iPhone is currently only for use with Mac OS X and you'll need to be a registered iPhone developer with the paid version of the SDK to properly evaluate the product.