radio install

the prelude i bought has an out dated pioneer in it. i want to put my jensen cd player in. the genius who wired in the pioneer didn't use a harness adapter so i don't know which wire are for what. if some one knows could you please help. i tried to find it on google but no luck so far.
thanks in advanced

Well, I'm not sure about Preludes, but here are the wires for a civic. They may be the same.

B+: W/B(blue) or W/Y
ACC: Y/R or W/R
Right front: +R/G -Br/Bk
Left front: +B/G -G/Bk
Right rear: +R/Y -Br/W
Left rear: +B/Y -G/W
Ill: R/Bk
Antenna: Y/W

what's b+ and Ill? thanks i'll see if the wires match up tomarrow.

B+ is constant voltage. Ill is the wire that will dim the radio when you turn your lights on.