We should try and get a decent list of groups worldwide who're utilitarian or obviously sympathetic to utilitarian goals - mainly as an exercise in curiousity, but perhaps we can also get in touch with them at some stage. Off the top of my head (I've linked some of these before, but collecting them seems worthwhile):

Utilitas - a journal of utilitarian ideas
Australian Centre on Quality of Life
Journal of Happiness Studies
The Wellbeing Manifesto (Australian)
International Society for Quality of Life Studies
International Society for Quality of Life Research
Charity International - a specifically utilitarian charity
Giving What We Can (not active yet)

Any more?