There’s an interesting discussion going on over at the fractionmag blog about photographers redoing their online portfolios to make them compatible for viewing on the iPhone and iPad. Definitely check out the thread, and I’ll add my .02 here. Unless you work in the rarefied postage-stamp genre, it’s probably not a good idea to show people your work on an iPhone. It’s just not going to look its best if they can see it at all. The iPad could be a different story because of its larger screen size, so maybe it will be worth addressing these compatibility issues.
Basically, the question is whether you use Flash on your portfolio site or not (if you haven’t heard, neither i-devices do Flash). I’ve seen quite a number of sites where the Flash antics actually overshadow the work and make it hard to get to. Your site construction should deliver your images cleanly and quickly, and you certainly don’t need to get tangled up in Flash to accomplish that. There are many good looking website templates, like this one by photographer Dalton Rooney, that get you where you need to go with maximum ease and don’t use Flash, solving your i-compatibility issues from the beginning.