I have the program to change the BIOS to booting up to a different file, rather than the xboxdash.xbe. My problem is that in the readme file it says I need the RC4 Key and I cannot find it anywhere!!!

Can someone help me out here please, either by sending it to me or pointing me in its direction.

Check this thread

http://www.cdrom-guide.com/forums/showthread.php?s=&threadid=205915