It's a fully fledged web-app, so you can hit up the "+" button when you go to the URL on you phone and it will install itself for you with a nice icon and it's all ajaxxy so it works proper an stuff... so.. yeah.
Didn't seem to work at all on my Symbian S60V5 N97 using the native browser. Haven't tried with the Opera browser, yet. I'm *guessing* it'll work with n900 but don't own one of them, yet.
edit: Also, if I can nut out what the problem is maybe we could look at a subdomain of 'm.aucdb.com'?
It should work fine on any webkit based mobile browser or one that follows the WHATWG HTML5.0 ("Web Applications") draft specification.
At a minimum it's gonna need javascript + html, since most of the functionality is ajaxian. If there's a large call for non-iphone usage, I could possibly expand this to work in non-ajax browsers, but I doubt there's even much call for iphone usage.