iOS 4.2 for the iPad was released today and as expected it brings the language capabilities of the iPad up to those available for a while now in the iPhone/iPod Touch, including Arabic, Hebrew, Greek, Korean, Traditional Chinese, etc. A full list can be seen in the updated iPad Tech Specs:
No keyboards are yet available for Indic scripts, even though fonts are present for Devanagari, Gujarati, Gurmukhi, Tamil, Bengali, Oriya, Telugu, Kannada, Malayalam, and Sinhala. (The full OS X still does not have the last 6 of these.)
For a full list of virtual and hardware keyboard layouts, see
I understand that the Keyboard Dock is available in the following layouts: English, German, Dutch, Spanish, Italian, and French.