GMail is now available on
iPad. Google launched a customized
GMail for iPad which is an experimental two-pane user interface to take advantage of its large touchscreen and tablet form factor. Building upon the Gmail for mobile web app, this new interface displays your conversations on the left and your messages on the right hand side.
Tablet devices are still very new, so expect changes as Google continue to optimize for this new format.

Recommended reading:
*
Fake GMail Account Verification 2010*
How do I make money with GMail*
iPad is slightly better than rock