Google is about to announce two new languages being rolled out for Gmail -- Arabic and Hebrew. You can find the announcement on their "What's New" page.
Gmail in two more languages
Now you can also use Gmail in Arabic and Hebrew. There are even some specially-designed features for right-to-left languages.
Along with these new languages comes a couple new tools to use when composing messages in right-to-left languages. These tools basically give the sender the option on a paragraph by paragraph basis to change the direction of text.