We feel like it would be nice to share with everyone the open-source and free-to-use products and services we use in DJs Music, to help others and to promote these great tools, so below is a list of all the ones we could remember:

JavaScript:

• Google Code: We use Google Code as a CDN for all the JavaScript we could find in it, it is both a very efficient server for those files, and it helps browse faster when users come with those files already loaded.
• jQuery: Is our preferred JavaScript framework, it is small, simple and very powerful.
• jQueryUI: We use this one for all our "interactive" widgets and animated stuff, along with jQuery it is one of the best frameworks for dynamic stuff.
• Several jQuery Plugins: BlockUI, scrollTo, sorter, Rounded Corners... etc
• SWFobject to load specific players

PHP:

• For PHP we have developed basically everything ourselves, with very few exceptions. 
• We use our own templating system, based on our URL Re-Writing schema.
• User management, Song reviewing, and all our main systems are all standalone services developed specifically for DJs Music.
• For some minor database tweaks we sometimes use phpMyAdmin, but we prefer our custom DB manager.

Other:

• We use some Flash components: The JW Player, and a Cover Flow in our Home Page.
• Databases in MySQL
• ShoutCast server for our Radio
  

And well, that is basically all I could think of now, if I remember anything else I will post it here,

Best regards,
Development Team