AccessCard: Links to Macintosh underground sites.
CowFight: Team of Macintosh underground developers, creators of ZapAttack, MacSmurf, SYNer and Cyanide.
Mac Hackers: Macintosh Hacking forums from Mac OS X security, development to system modifications.
mSec: Developers and administrators dedicated to forwarding the MacOS as a viable and secure network server environment.
Nessno: File server information, downloads and links for the Macintosh.
Team2600: Team2600 is the oldest Macintosh-only underground group now defunct and unmaintained.
Thee Gran Dive X: Commentary, links and reviews with an underground perspective.
TUW: Fever's updated list of underground links.
WDSecurity: Homepage of WeeDo, developer of GrouchySmurf and StreamEdit.