Is there any official AppleScript documentation? If so, where can I find it?
Almost all of the Mac developer documentation from Apple exists in several places. That being said, you want the unofficial Mac OS X Automation guide put together by Sal Soghoian. He also has a fabulous book on the iBook store titled AppleScript 1-2-3.
Xcode is the tool that links into these libraries and allows you to search across the various user guides, developer guides, language specifications, code examples and such.
Here is Xcode (with 10.6 and 10.7 documentation sets) and a quick AppleScript search.
Xcode makes it easier to bookmark, search and use the documentation rather than just browsing in Safari since it will download the whole
Of the 232 matches in the System Guides - about 10 cover AppleScript in depth - the rest refer to how programs make themselves available to be scripted by AppleScript.
The official AppleScript langauge guide can be found here. Since its a PDF, it's compatible with iBooks.