I am doing this by using BeoPort, which is a black box connecting a PC/Mac to a BeoSound using USB + analogue audio as input and MasterLink as output. You will thus need a BeoPort and some MasterLink cable between the box and your BeoSound. It is almost plug and play, and easy to use.
It is however difficult to retain overview of many MP3's, as the BeoSound does not give you any feed back. You will be able to step between tracks and play lists, and change the volume of cause.
The BeoPort will also add N.RADIO to your system giving you thousands of radio programmes to chose between.
I bought my BeoPort because I wanted to listen to MP3s, and I do this from time to time, but I never imagine how useful the N.RADIO function is, and I use this function now more than the MP3s.
Living room: BV7-40 mkIV + V8000, BL5, BL3, BM1 and BS9000. Bedroom: MX3000 and BL4500 on MCL2-AV. Around: PentaIII, CX100 and MCX35 on ML/MCL + MCL2-A, BeoPort and BL4 on ML, BS3300 + M75 as stand alone, BC6000 + BC600 and BT1100, LC1, LC2, Beo4, Beo5 and BL1000, BS2 and A8, EarSet2, Apron, Coffee mugs, Enamel Bagdes, Bath towel, Keyring, Books, Lots of miniature and the Bottle opener. Office: BC2300 + BL2500 and BS3. Summer house: BS Century.
Addicted? Oh no.... ;)