Sorry should not have originally named the page as copyurl.htm please see this link

• http://www.mvps.org/dmcritchie/firefox/copyurlplus.htm

or perhaps one of these links, if you see #userjs on the end at the url named in the location bar from the link.

• http://www.mvps.org/dmcritchie/firefox/code/user.txt
• http://www.mvps.org/dmcritchie/firefox/copyurlplus.htm#userjs

or specifically to locate your current Firefox profile
which has been simplified in Firefox 3 as all you need to do now is
Help [Alt+H] → Troubleshooting Information... → "Open Containing Folder"