Firefox & Thunderbird App Data Directory

How do I change the default directories which FireFox and Thunderbird use to keep data in Windows XP? I want to install the two apps onto a flash drive to use at the public library computers but I also want any data to also be keep on the flash drive. And not in C:\Documents and Settings…

I want to change the use of C:\Documents and Settings…\Application Data to FlashDrive:\Data.

There are “portable” versions of both FireFox and Thunderbird out there that do exactly what you need. I believe that transfering your email and bookmarks to the flash drive versions is a cinch.