The iOS 5.1 beta 1 SDK is now available for download by paid devs at the iOS developer site. Sign in with your developer credentials to gain access to the updated SDK. You will need to download and install firmware via iTunes and cannot use over-the-air updating for this initial release.
Because it cannot be said too often, make sure you read any release notes on-site. For everyone intoxicated by new technologies that might allow you to update using other means, I cannot strongly encourage you enough to go to the site and read the release notes. This hint goes out especially to those of you who are not primarily developers but have purchased dev accounts to stay current on the technology.
Installation alerts appear in a big yellow box on the main iOS dev page. The yellow box for 5.1 is larger than ever. Important update notices also appear on the developer forums. If you run into troubles installing updates, please check the dev site and forums first.
If you don't have access to the dev site and forums, please don't e-mail us for technical support about the iOS 5.1 beta. You install the beta, of course, at your own risk.
As a final note, don't forget to register your device at the developer portal and prepare it for development before installing the new beta.
The beta is, as always, released under the terms of Apple's NDA. For that reason, enhancements, APIs and features are not listed within this post.
Happy developing everyone! Thanks, everyone who tipped us.