[From Dartanion London] My favorite mobile app these days is
Evernote. I make a lot of notes and lists, and with Evernote, everything always stays synced. They're still working out their pricing structure, but the beta/free version gives you 40 MB of uploads a month. Your notes can be bigger, that just reflects how much new data can be transferred. So far, there's only a windows mobile version, but Jave ME and iPhone versions are in the works. However, if you have a different phone it's just as easy to log on with your phone's browser to access your notes.