Hey Michael,
I'm afraid I don't really know of one all-encompassing Disney site. If you find a good one let me know!
Adopted Batpuppy, I have been to comic conventions, but all of them had tickets sold on-site. The San Diego con, from everything I've heard, is a whole other ball of wax. You need to really keep up with the information as it leaks out because - as you also heard - tickets sell out in advance pretty quickly. I'm really not super knowledgeable about the show, so I'd just forward your questions to whoever runs the main Comic Con website, or read their Frequently Asked Questions section, if they have one. Good luck to you though! I'm not sure the show is really worth all the hype it gets, though. The people I've spoken to all say it's now overrun with films trying to get extra press, whereas it used to be purely about comics and cartoons.