In today's presention regarding the next version of iPhone software, which is supposed to be released sometime this summer, Apple indicated that it will include new languages and keyboards.
Unfortunately I have not found any info yet about which ones (though I would expect at least Arabic/Hebrew, Greek, and Thai might be among them). If anyone has details, let me know.
PS As of 3/25 I have seen online photos or other reports indicating new keyboards are available for Arabic, Greek, Hebrew, Indonesian, Malay, and Thai.
PSS Apple issued the tech specs for the iPhone with 3.0 software on 6/8/2009. It confirms UI, keyboard, and predictive dictionaries for Arabic, Thai, Greek, and Hebrew.
PSSS When made available 6/18/09, 3.0 has off/on switches for two keyboards not mentioned in the tech specs, Bulgarian and Macedonian. But these keyboards do not work.