As Apple approaches the sale of the 1-billionth song on its iTunes music store, it has launched a promotion — giving away Nanos and gift certificates to the lucky purchaser of each “100,000th” song. But the grand prize, for the 1billionth song: a 20-inch iMac, 10 60GB iPods, and a $10,000 iTunes Music Card. $10,000 in music and videos?!? Wowza! Right now, songs are selling at about 100 every five seconds — that rate can only get faster as the “clock” gets closer. It’s at 955,232,874 right now!