I’ll admit it, I spent a good 20 minutes trying to figure this out before finally searching the web enough to find an answer. I already knew where all the firefox information (bookmarks, stored passwords, etc) was stored on the Windows side, but I had a heck of a time figuring out where these were stored on the Linux end. Doing a file search showed that /etc/firefox/profile and /usr/share/firefox/ looked to be close, but it turned out that these were the wrong locations, and replacing those files did absolutely nothing for me.
So where is your firefox profile actually stored? It turns out it’s in a folder with a crazy name (like p7tupxmb.default) and is located in:
/home/username/.mozilla/firefox/ (where username is obviously your own user name)
So in my case, all I had to do was copy everything from the following location in Windows XP:C:Documents and SettingsusernameApplication DataMozillaFirefoxcrazyname1.default
to the Linux directory:
Keep in mind that crazyname1 and crazyname2 will be different (for example, p7tupxmb.default and qs4ks3d2.default) , so copy the contents of crazyname1 to crazyname2 (or copy the folder and just rename it). Be sure to make a backup first before replacing the Linux one in case something goes awry.