Well, I've tried a different branch of Starbucks and managed to log into the T-mobile hotspot with no problems (and no special software/config required). I've still not been able to get into any BT Openzone hotspots though.

As the places I travel to regularly have a Starbucks in town/at the airport/station then it makes the 770 useful enough for me to keep. It would be nice to be able to use it with BT Openzone too though. Has anyone else been able to do this?