Two posts to read:
http://www.greekchat.com/gcforums/sh...d.php?t=100682
http://www.greekchat.com/gcforums/sh...d.php?t=105943
And the best way to get your brothers to approach and talk to potential members is to pair them up. I know that meeting and talking to someone one-on-one can be intimidating, so give everyone a "recruitment buddy" that they can use when wanting to meet and talk to someone new.
Also... Facebook is your friend! I can't emphasize how useful this can be for introducing your organization to potential members, and for keeping in touch with the ones that you know. Create a group, send mass messages, befriend guys, write short messages on their walls... It's a lot less intimidating and can be very effective.