I've been picking 2-finger style for a long time. You can listen to a couple of mp3's at Banjo Newsletter's site. Look for Wearing of the Green & Dead March in the mp3 archive.
http://www.banjonews.com/index.html

My all time favorite 2-finger picker is Will Keys. Follow the link at his site to his Kennedy Center performance. Will is from E. Tn. and is an absolute master of the style.
http://home.att.net/~wk2finger/index.html

There has been a discussion of various finger styles, including 2-finger, at banjo-l recently.

N. Ga., E. Tn., & W. N.C. have a long tradition of 2-finger picking.
Get hold of a copy of Art Rosenbaum's "Old Time Mountain Banjo" instruction book for an excellent overview of these styles. Amazon.com still had some of these recently.

Chip Arnold