The official Gingerbread guide has been spotted online and it looks to be nearly 400 pages of “how-to” for Android 2.3. As mentioned early in the book (PDF), this does not cover the Nexus S, nor any other specific handsets. Rather, this is to help familiarize one with the benefits and features of the latest release of Android. For many of you, this stuff is old hat. For others, this could answer those sticking questions you have.
Download and/or read the full PDF (6.1MB) file for yourself!