If you have any questions or requests for tutorials, post a comment or pm me.
You can convert the bat file to a exe if you want with this free software
To make the new profile
firefox.exe -ProfileManager -no-remote
The script fort he bat file to open Firefox 3
cd *(1)C:\Documents and Settings\Administrator\Desktop\firefox
firefox.exe -P *(2)firefox3 -no-remote
*1(remember, this needs to be the location of your firefox 3 exe)
*2(make sure this is the same name that you gave your second profile!)
This whole process can be done the same way if you already have Firefox 3 and wanted Firefox 2 at the same time.
Firefox 3 Portable
Latest FireFox 3:
JimmyR talking about Firefox 3: