I play it on 360 and am currently in two crews.

Gaming Furever: http://socialclub.rockstargames.com.....gaming_furever
- If you're not already aware of them http://www.gamingfurever.com/ is a gaming community, review, solialising, etc site for furs into gaming.

FA: http://socialclub.rockstargames.com.....ew/furaffinity

Furry Shooters: http://socialclub.rockstargames.com.....furry_shooters
- Don't know anything about them but they have the largest membership I've seen so far for furry crews.