Question on what is involved in building a script like this

http://www.zoomclouds.com/ how difficult is this and what cost should I be looking at ball-park. What is the best langauge for this to be programmed in?

thanks

 

do u wanna build somtethn like this sitetagged.com

 

I have seen those scripts and they are pretty cool but the great thing about zoom cloud is that you can setup the tag cloud on your site and when people click on links it goes to their site and shows your topic but they have their adsense up.