What Scripts/code's do you need to know?
 

What Scripts/code's do you need to know to make a WOW Addon? And What books are good for teaching about them?

If you have ever programmed anything, you can pretty easily code addons for WoW. Just look at what other people have done and their code samples :)

Also, feel free to ask questions. You can get answers here, at the official WoW forums, and now at irc.freenode.net #WoWI-lounge

:)

Primary code language is lua by the way, but it is different than the normal lua in several ways. You can find a guide at http://www.lua.org/manual/5.0/