If I did this right, you all ought to be able to click on the link and pin yourself on the map. You can do it with your exact address or only the city. I hope this works.
Rockstar Forum Members Map
If it doesn't work, someone let me know and I'll keep messing with it. Or if there's no interest in the idea, just let it die.
P.S. Just so you know, this map is only visible to people who follow the exact link above. I'm not super-paranoid, but I'm not excited about sharing too much info out there.