The 6 disc cd changer in my Disco went out on me a few weeks ago so I decided to have the Mp3 adapter plug-in installed on my OEM Alpine radio offered by GB 4x4 Radios.
After contacting GB 4x4 Radios from their website, I was emailed excellent instructions on how to remove and ship my factory radio to them. The whole turn around time was less than 2 weeks with a cost of $144.
I got it back today, installed it back into my disco (takes about 5 min) and plugged in my Sansa Mp3 player into the 3.5mm jack they installed in the face of my Alpine radio and began listening to my tunes from the Sansa.
All I have to say that it is fantastic. Very high quality sound, no static and now I don't have to deal with the hassle of changing CD's under the seat. If you are considering doing this, it is great. You won't regret it.
Here is a link to the website.
USA | GB 4x4 RADIOS

 

if anyone is in a hurry his guy sells them already done, no exchange for 195.00.
and they no longer need a unlock code.
Land Rover Cassette Radio MP3 iPod SAT Aux Audio In | eBay