For all of our developers out there in the community, or folks that just want to experiment, you will be happy to find the following download links. We have the Ice Cream Sandwich System Dump and Data Folder Downloads available!
Also, Google has already released the SDK for the 4.0 version of Android, which you can find at the Android Developers source link below.
Downloads: Ice Cream Sandwich System Dump & Ice Cream Sandwich Data Folder
Source: XDA-Developers and Android Developers