Some information about Apple iTunes Music Store...
The article said ...
Macworld writes that a recent report released by NPD Musicwatch showed that 25-percent of the songs purchased in the United States during the first months of 2009 came from the iTunes store. That makes iTunes the most popular music retailer in the country, beating out former champ Wal-Mart, which boasts 14-percent.
I remember when Apple announced that the Apple iTunes Music Store became the Number 1 music retailer in the country, bypassing Walmart... :-)
Some of these cover versions I picked up on iTunes but many others on eMusic. Also, if you surf around, you can pick up tons of free cover music by up-and-coming indie bands who have not signed to major labels yet (and likely never will). Many of these cover songs are quite good.
Another good source for discovering good cover music is the Podcast "Coverville" by Brian Ibbott.
I have a cover playlist of 1,722 songs.