Cody writes -
I purchased an iTrip off eBay for $30 shipped. I wasnt expecting it to work good due to the many negative reviews I have read about it. I started off by pulling the antenna out of the case for a better signal. It did increase the performance, but not enough. I found this article and decided to make one. First off, Radio Shack was only good for2 things, battery snaps and a battery. I purchased everything from www.allelectronics.com. The article linked above describes using a 12v car adapter, I wanted to make it portable so I am using one 9v battery. I had a 12v 200mA AC-DC adapter, it fried 3 transistors so I dont recomend that. T Here is the part list for www.AllElectronics.com, but keep in mind that the resistors and transistors have small minimum amounts for purchasing...
cparsell - iTrip Amplifier - Link.
http://blog.makezine.com/archive/2007/02/diy_itrip_amplifier.html