Portable Firefox and Thunderbird
Run Firefox and Thunderbird from a removable/USB drive!
Portable Thunderbird 0.9 (USB Drive-Friendly)
Thunderbird supports running from removable drives with minimal reconfiguration. To make life even easier, I've repackaged Thunderbird as a complete, removable drive-friendly email client.
Portable Firefox 1.0 (USB Drive-Friendly)
Portable Firefox is a fully functional package of Firefox optimized for use on a USB key drive. It has some specially-selected optimizations to make it perform faster and extend the life of your USB key as well as a specialized launcher that will allow most of your favorite extensions to work as you switch computers. It will also work from a CDRW drive (in packet mode), ZIP drives, external hard drives, some MP3 players, flash RAM cards and more.