Hey Ben, this is a very good idea! iPhone's mobile Safari is very capable and the site is very usable already. But the same cannot be said for PIE (pocket IE). I haven't browsed it using mobile Opra so I wouldn't know. I can see the advantage of A2OC-on-the-go, imagine you're driving to a garage/dealer to get something fixed, you can immediately reference stuff on the site, which is the best resource for everything A2!
A few things I can think of, the menu can be optimised.
It works on the iPhone, but it may be easier if somehow the 'expandable' menu like Search can be more accessible.
Viewing Picture Attachments. I think the site's implementation is great, love it. But it seems phone doesn't like that, neither does it work on PIE.