Firstly,
glad to see more dev getting into mobile mods for x-cart. Any chance of getting one made for version 4.0.xx? Had to ask
OK, some feedback from my iPhone 4:
1) Contact us page. Could do with some padding, text touches screen border. Just a visual thing. Fields also don't resize, so currently are wider than screen.
2) Returns link not working
3)Home and Store link go to same page, only Home has an image. IMO lose the Store link, Home is better and less confusing.
4) Don't think you need a Back button, again, only a visual thing.
5) No checkbox for "accept term and condition" in checkout. Not sure of legal implications, but I actually like that it just mentions it, because its really just obvious that you accept it anyway, but you might have to have a tick box legally for any future issue. UPDATE, just seen it on the Place order page. Don't think its necessary to have on Payment page then
Otherwise, GOOD JOB guys. Well done.