Depends how much coding you know, and also on how much you want to know. Are you looking for somewhere you can dowload lots of scripts, or are you looking for help in writing your own?
They have their uses. I've noticed of late that some sites are using some kind of funky script that they run in a small popup window when you click on a download link to avoid that yellow bar in IE.
Pop ups are just annoying when used badly or for advertising. Just my own opinion of course.