10.5: Modify group memberships in 10.5 – Mac OS X Hints http://hints.macworld.com/article.php?story=20071101100044328
macosx – Apache runs as which user, group under OS X 10.6? – Server Fault http://serverfault.com/questions/152175/apache-runs-as-which-user-group-under-os-x-10-6
How to Install WordPress on Mac OS X (Leopard) http://dancingengineer.com/computing/2009/07/how-to-install-wordpress-on-mac-os-x-leopard
osx – How to add user to a group from Mac OS X command line? – Super User http://superuser.com/questions/214004/how-to-add-user-to-a-group-from-mac-os-x-command-line/214311#214311