I know that Kelly have been working on an iPhone app for Hamshere, but as far as I know it's not ready.
Part of the problem, I guess, is that Ios don't support flash. This makes it impossibel to run HS on iPhone / iPad. But there is a large demand for such an app, so I'm pretty sure it will come in due time.
Untill then we have to run HS on our computers :-)
If you browse this forum you can read many threads about this subject.