AFPEx is not a website - it is a client-side Java application of about 3MB in size.
AFAIK no current "phone" device runs it. The Ipad might perhaps???
In general, www-capable phones can access most normal websites but there are occassional issues because these browsers are not quite Internet Explorer compatible.
I have a pocket/pc PDA (Fuji LOOX N560) on on that I have Pocket Explorer and Opera; one works on some sites and the other works on some others
That said, pocket/pc is crap anyway and I am sure the more modern stuff like the Iphone are a lot more compatible.
My Nokia E51 runs most small aviation weather sites OK, but the panning is painful at times, so I use it for tafs/metars only.
IMHO, preflight stuff needs a laptop. Can be a very small one but anything smaller than a laptop is just painful. Unless one is happy to skip some steps, like getting notams
