I need to know where in mac os 10.6, does the bookmarks file reside?
Go to Help > Troubleshooting Information, then click on Show in Finder. That will open the Finder in your Firefox profile. Your bookmarks are history are in a file called places.sqlite. There's also a daily JSON backup of your bookmarks in the folder called bookmarkbackups.
More info: Profiles - Where Firefox stores your bookmarks, passwords and other user data