Thank you for the info, Polonus. Other Firefox users might want to know that disabling the Geolocation feature is absolutely unnecessary. It does not gain a Firefox 3.5 user any additional privacy, since it is 100% opt-in. No site is given the location of a user’s computer unless the user explicitly enables Geolocation for an individual site when the site requests it. I think it’s all explained in the link nmb supplied.
Disabling Geolocation in about:config will merely prevent the user from ever being asked, so I suppose setting it to false would be useful if being asked turns out to be irritating.