I'm going to say how I do it, not whether it's ideal, but just because it works for me. I unzip http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-mozilla-1.9.2/firefox-3.6.5pre.en-US.win32.zip into the stick then copy my [http://kb.mozillazine.org/Profile_folder#For_Windows_users profile] from the pc to a folder I create on the stick named '''myprofile''' I then create a shortcut on the stick to the .exe on the stick with the following in the '''Target''' box of the shortcut properties: "E:\firefox.exe" -no-remote -profile "E:\myprofile" Obviously you'd need to edit that to whatever drive letter your stick gets assigned by the PC it's plugged into, but I've found over 90% of them assign E: to it. If no Firefox is installed on the PC then an empty 'mozilla' folder is created in the %appdata% location but nothing is saved there because I'm directing it to look on the stick for the actual profile.

Use the portable Firefox version. See http://portableapps.com/apps/internet/browsers/portable_firefox