The redoubtable Brigid Alverson (of Comic Book Resources) posted a good round-up of the various comic reader apps available for the IPhone/IPod Touch. There's actually a lot on there, once you get hold of a portal app such as Comixology or Iverse.
I think the IPhone market is going to be a huge and I see a lot of indie comics creators adopting the platform to push their work. I read a lot of stuff on my IPod. It's the comics equivalent of an mp3 player; I just load it up with comics and then I can dip into a comic whenever I'm sitting on a bus or having root canal treatment.
Ironically, I think consuming comics in this way might be closer to the throwaway pulp roots of the medium than the wrapped-in-uv-protective-plastic, fetish culture that developed in the 1990s.
After a bit of testing I've come to prefer the ComicZeal reader, which combines a good display (it stays clear even zoomed in), PDF support (I don't just read comics on it) and very easy-to-use syncing.
I'm not holding my breath for the mythical Apple Tablet (aka "The Big Ipod Touch") - which is supposed to CHANGE THE FACE OF COMICS FOREVER!!! - but apart from the size (an inch longer and wider and it would be perfect), I see little wrong with the current platform.
(via Robot 6 and Forbidden Planet)