Their site is at
Home: AIGA.
It's the American Institute for Graphic Arts, although it's an international organization (How American of them
).
To sum it up, it's a little like a GA's Guild.
they deal with the ethical/societal/environmental/etc. isues surrounding GA
- promote our profession as a profession
- organize huge international seminars/shows/competitions
- organize small local seminars/shows/competitions, stimulate local design communities/networks
- all sorts of nice things like that.
If you're unfamiliar, I suggest visiting their site. They can explain it better.