I have found something here which I have tested and works incredibely fast.
http://www.ngcoders.com/downloads/fr...nloader-script.
It is a free script just using Curl and PHP. It gives three options MP4, 3gp and flv. I want to try and get it to work with mp3, and was wondering if someone can take a look. I think just a little change similar to what you have done before with 3gp conversion could achieve this. I tried myself but I am just learning.