We're all waiting for news about the release date for both the Galaxy Nexus as well as the Ice Cream Sandwich update for our existing phones, but in the meantime Google has already released the Ice Cream Sandwich SDK for those of us who like to tinker around. Of course the website is slow, and so is the SDK manager to get the files, but keep at it -- Google has lots and lots of bandwidth.
You can update your existing Android SDK installation via the SDK manager program, and hit the source link to read a bit more. Here, hand me your phone and I'll Beam it to you.
Source: Android Developers