where do you get the codes for pop up windows?

DO you mean just opening a link in a new window? Add target_"blank" to your link, or something liek a javascript link, thats here:
http://www.lissaexplains.com/javascript4.shtml

www.dynamicdrive.com have a heap of good effects and window goodies you can do, it has plenty of different ways you can have a popup window

this also includes removing all the annoying go buttons and all :)

I love dynamicdrive.com Its a great site. Oh one more resorce you could check: Funky-chickens.com