Here's a little screencast:

There are obviously a number of bugs, including the fact that none of the contacts from your phone show up in the buddy list, so you can't send new messages. Try using gnome-phone-manager itself for now, but the future lies here.
PS: Get your distros to update gnome-phone-manager. Fedora has the latest versions in rawhide and Fedora 8. Some distros *cough*buntu*cough* still ship ancient versions.
