My own setup is iTunes to Airport to BeoLabs.
The part coming from the BeoLabs is "Cable - External Line" which is a DIN to RCA male as mentioned above. It is a B&O product and the part # is 6270856. You'll need one for each speaker. From there, you will need an RCA female to mini stereo adaptor.
Here's the tricky part. Don't plug the mini stereo directly into the Airport otherwise you'll blow your speakers (per my own experience). The Airport puts out a very strong signal. You will then need a headset in-line volume control to attenuate. (Its a volume control that goes from a sports earset into an ipod for example.)
The in-line volume control goes between the adaptor and the Airport. Adjust the volume control to about halfway. The volume control then goes into the Airport.
I have iTunes on a Mac. The Mac "sees" the Airport and asks you whether you would stream music thru Airtunes (the answer is yes). You can then control the volume remotely from iTunes.
It works splendidly for me. I have three sets of B&O speakers each with an Airport. I can run 1 room, 2 rooms, or all three thru iTunes.
Oh, and if you have the BL8000, you wont need the B&O din to RCA. You'll just need a set of RCAs - male at both ends.
Hope this helps, and sorry if there were any redundancies to the posts of others.