iTunes music sharing

So I wanted to borrow my buddy Jim’s CD of Seussical the Musical, in light that it’s coming to town this month, and my wife and I want to take in one of the shows.
Jim says it’s loaded in iTunes, just connect to his shared music. Once we figured out that iTunes wants our IP addresses (different subnets here at work), I’m listening to John Williams – Greatest Hits 1969 – 1999 (greatest composer of the latter 20th century?), and Jim’s reconnecting with his teenage years by jamming to Bon Jovi’s Slippery When Wet on my TiBook.
It’s wicked fast, with no lag. This despite the heavy traffic on our corporate network and the fact that our Macs are both streaming and receiving at the same time. Apple rocks.