Google Maps Mobile is now available. It runs as a J2ME Midlet, and works fine on my SPV C500.
Simply navigate your mobile device here, and choose the "High spec phone" option (or something similar). It won't display the satellite images though; it claims my phone will not display JPEGs. Perhaps the Java machine on my phone won't, but my phone certainly can.
No way to add push-pins, which seems like a strange omission. First thing I always do is push-pin my house so I can do directions.