Creating an extension in Firefox

http://developer.mozilla.org/en/Building_an_Extension

This tutorial helped me to create a sample extension displaying my name in the status bar

Install Error Console add on to see any error in your extension code

After trying out if you don't get the message in status bar

Check error console for error

If you got an error saying

Failed to overlay ....................

Then  in your chrome.manifest you would not have added / after the path

(Don't forget the trailing slash, "/"! Without it, the extension won't get registered.)

This is the error i got while creating my sample extension .Then rectified it