Adobe already has Photoshop Express available for iPad and iPhone (previously photoshop.com mobile). This is, however, only a light-weight version of the software greatly lacking in features comapared to the full Photoshop experience.
That's all going to change soon. Adobe demoed a new full version of Photoshop at Photoshop World 2011. Here's a brief clip uploaded to YouTube, which shows the new Photoshop in action:
The way this version handles layers looks particularly cool.
A fully-functioning version of Photoshop for the iPad (and other tablets) would no doubt make the devices an even more attractive option for businesses/enterprises. Of course, there are already plenty of apps in the App Store that can easily be used to replace many features of Photoshop (for a lot less money, I might add), but Photoshop is still the leader of its genre of applications.
Adobe has not put a release date on Photoshop for iPad, but designers and businesses that are already heavily using iPads will certainly be eagerly awaiting it.
On a related note, Adobe also introduced the Photoshop Family Feedback site at feedback.photoshop.com. This is simply a place where users can leave ideas and requests for the Photoshop team, as you may have guessed. This could be particularly helpful in the development of the new iPad version.