Hi,
it's easy to record your vinyl to your new Mac without problems :-)
What do you need?
Free recording- and editing-software called "Audacity" from here:
http://audacity.sourceforge.net/download/mac
Then you need a cable from your Beosystem to your Mac. I don't know the Beosystem 6000 so I don't know which plugs it has. I need a little help from you there :-)
The DIN-plug from your Beogram does NOT work because a turntable always sends out some kind of "disturbed" signal that will be corrected through the phono-amp in your Beomaster!
If you have RCA-plugs (or "cinch" here in Germany) you need the following cable from your Beosystem to the line-input from your Mac:
http://www.technikhaus24.de/images/product_images/original_images/00043333abb.jpg
If you have a simple small headphone-plug on your beomaster you need this cable:
http://www.preisvergleich.org/pimages/Audio-Kabel-Hama-35-mm-Klinke-35-mm-Klinke_96__592378_40.jpg
This is a 3,5mm plug. If you have the "big" headphone-socket on your system you'll need a simple adapter for the cable above, too:
http://www.playdeluxe.de/bilder/hifi/klinke63_35.jpg
Connect headphone out to line-in of your Mac, start some music, start audacity and then you have to watch the levelmeters in Audacity at first. They should stay below 0dB on the loudests part of your music; otherwise the recording will be disturbed!
A good tip for recording: Start the recording on your Mac and then go to your Beogram and start your vinyl! It doesn't matter if there's a big pause on the beginning as you can cut it out with Audacity :)
If the Beosystem has only DIN in- and outputs you need a special DIN-Aux-cable from your B&O dealer or you'll make one by yourself.