Finally got found to playing with my Nokia 770 over Christmas. It's a very cute toy, although the email application it ships with is a complete pile of crap. But now I have pine running, I'm happy again.
Although it's a text-mode application, pine actually works really nicely on touch screen devices with its 'enable-mouse-in-xterm' mode. It uses the xterm escape sequences to capture mouse clicks, and you can tap on menu items and actions on the screen, and navigate through folder trees and indices just by tapping on them. You only ever need to resort to the 'keyboard' to actually compose a mail.
In conjunction with xterm running full-screen on its 800x480 screen, it makes the Nokia 770 into a really nice box for roaming email access.