I think this probably has been mentioned before, but I didn't read the entire thread so excuse me if I offer advice that has already been offered!
I actually have a section on the bottom of my resume for volunteer experience where I go into more detail about offices held, etc and a separate memberships section. Volunteer experience has my specifics for AOII and Rotary with dates/years while memberships are those orgs that i'm just a member of (Girl Scouts, Sons of Norway, NTHP, reenacting, etc - and I didn't list EVERYTHING I've a member of).
I also have a separate format for more field related positions rather than just your everyday pay the bills jobs. I also have my CV separate to be sent with the resume for those positions that would need that kind of info.
Sarah