An interesting story on NPR, reviewing a documentary called "Sounds of Silence," by Amir Hamz and Mark Lazarz, on Iranian rock and rap. It includes samples from O-Hum, Barobax and Hich-Kas.
Go here to view a video by rap group Hich-Kas. Download songs by Hich-Kas here. Go to the Wikipedia article on Hich-Kas to find more zipped mp3s.