I have web sharing turned on in the prefs pane, port 80 forwarded to my machine, etc, etc. When I try to access anything in the ~/Sites folder for my main user, I get "Forbidden. you don't have permission to access /~username/ on this server." It works with a different account on my machine, no problems. Permissions on the ~/Sites folder that doesn't work are set the same as permissions on the other ~/Sites folder that does work. They are both Owner: me, Read/Write Group: Staff Read Only Others: Read Only.
Any idea what I might do to get this going on the user account that isn't working?