8. May 2010 02:35
This took me way too long to figure out, so I hope it helps some folks.
Seems that $('#yourtextarea').scrollHeight doesn't work. Instead you need to do $('#yourtextarea').scrollHeight.
Example (scolls to bottom of textarea with id "console"):
var psconsole = $('#console');
psconsole.scrollHeight - psconsole.height()