gdmphotosetup should have name User Properties and should have ability to
change current user password, name and other information. At least basic
passwd frontend would be very usefull.
I've discuss this with the people from gnome usability channel:

<mantas> Gnome has usability hole, because there are no way to cange
password for simple user :(
If I'm simple user and I want to change my password I should run a command
line. This is bad for desktop environment
<daveb> no i agree, but that sort of ui should most likely be added at the
distro level, even though it's open to debate
<murrayc> mantas: A users control panel would make more sense.
<mantas> murrayc: there is users control panel already in
gnome-system-tools, but this is not suitable tool if simple user want to
change password or some other personal info like name
<mantas> users control panel is for admins
<murrayc> mantas: Good point. Maybe it could be in gdm.
<daveb> murrayc, it could be integrated with the face browser
<daveb> and some other user specific id stuff