I poked around on
http://gimp.org the other day but didn't dig up anything on downloading brushes. I found a few other sites too, but didn't find anything too useful. But ya, GIMP is kinda part of an "underground" culture (from how I see it) therefore getting into it can be a little tricky. BTW, I'm downloading GIMP 2 today - woo woo!
The kind of brushes I'm looking for in particular are those helpful in creating backgrounds, like those grimy alley walls, criss-crosses of splatters, gears, that sort of thing.
Sorry to hear about your HDD. Data loss =
Get GIMPed y'all.