How to Develope Add-ons for MOZILLA FIRE FOX 2.0(or)3.0?

[C++ Programming]

Hi,
Can you please let me know,how to develope sample Add-ons(code) for MOZILLA FIRE FOX BROWSER (i.e)Browser Handler Object?
Further,please let me know the ways to load & unload them once I launch & unlaunch FIRE FOX ,and its code base.
I am using C++(Visual Studio 6.0 IDE) to develope it and MOZILLA FIRE FOX 2.0 & 3.0 as BROWSERS.

Please help.

http://www.barakasoft.com/script/Forums/Images/smiley_confused.gif

Thanks in advance,
V.NATARAJAN