I noticed that my iChat-related AppleScripts had stopped working after the 10.8 upgrade. Apparently, Messages no longer answers to the name iChat; you have to edit your scripts to call "Messages" instead, like this:
tell application "Messages" to set status message to "On Mountain Lion"I'm pretty sure the beta didn't break backwards compatibility like that, and I really can't think of a good reason for it.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20120809225128119