I went down to a get-together in Laguna Beach today, and of course I took the train and OCTA. Part of my reasoning in doing this was to test my T-Mobile G1's mobile internet capabilities, and I'm proud to report that they're working well. 3G service in Orange County provides ~600kbps, even from a moving Metrolink train, and EDGE service provides passable data (~150kbps) in less-benighted parts of the world (read: Riverside). I'm very happy with it, and I can see how this will improve my soon-to-be-daily commute to Los Angeles significantly.
I also did a bit of railfanning at the Santa Ana depot while we waited for our train. I'll be posting the photos shortly.
Anyway, for all of you transit riders, I heartily recommend the T-Mobile G1 (with Google). It's an invaluable resource for checking maps and timetables, especially when you're riding an unfamiliar system. One annoyance is that the Google Maps application, which is otherwise great, does not yet include Google Transit data. (Neither does RTA, for that matter.) It does show the locations of stops and stations, but not the services and schedules at those locations. Google promises they're working on it. Otherwise, it's a solid device and well worth the outlay.