On public computers it is important to change the settings so it deletes the history file when it is closed, rather than after 30 days which is standard setting. Although firefox’s history files are securely in weird .MORK files but they can be accessed with a perl script called Mork.pl They are still accessable from their hidden history.dat file which can be opened with Notepad.
In XP- C:\Documents and settings\USER\application Data\Mozilla\Profiles\PROFILE NAME\history.dat
In Linux- ~/.Mozilla/profiles/PROFILE NAME/history.dat
OR from the [[cookie]] data In
XP- C:\Documents and settings\USER\application Data\Mozilla\Profiles\PROFILENAME\cookies.dat
In Linux ~/.Mozilla/profiles/PROFILE NAME/cookies.dat
also in linux browse this URL- about:cache