Hi Ron,
There is a client for iPad but it doesn't fully integrate graphics -- it's more for chatting and media, sending and receiving Linden Dollars, etc. You can read more about it here: http://goo.gl/ec0EN
The implementation for the Mac the full viewer, available both from Linden Labs and from 3rd parties. In fact I'm using it right now. There's a big difference between a Mac and an iPad, but with the new iPad 2 that comes out this month (dual core processor and 9x time faster graphics than original iPad) who know? If Linden Labs doesn't develop a version for this new iPad perhaps a 3rd party development group such as Phoenix might tackle it? But that's just a guess.
Jerry (aka Groovy Greenberg)