This was originally posted by Alicia here:
http://artshantymaps.blogspot.com/2008/10/piles-of-links.html
Here's lots of interesting people, groups, and collections to look at. Most of them are related to psychogeography. So to start with, for what it's worth: http://en.wikipedia.org/wiki/Psychogeography
PIPS is a collective in Providence, RI. They do all sorts of projects but most notably put on the Provflux festival every year: http://www.pipsworks.com/