Tucked away in the update notes of Nokia Ovi Suite v188.8.131.52 is this: "Nokia Ovi Suite now supports syncing contacts with Mozilla Thunderbird 3.1". That's really significant for me, because the ability to sync my contacts with GMail is something I've been waiting for, and I know I can go via Thunderbird. I don't know yet whether it can sync calendars with Thunderbird, though.
Mokalus of Borg
PS - Technically, I think that would be synchronising with the Lightning plugin.
PPS - And surely if they've done contact sync, they're aiming for calendars too.