Apple passes Wal-Mart in music sales?

Tech blog Ars Technica says they've got their hands on an internal Apple memo that shows iTunes has topped Wal-Mart Stores in total global music sales.

The data in the memo cites a report from the month of January conducted by The NPD Group, a market research firm. NPD's numbers show the iTunes Store leading overall music sales for the first month of 2008 with a 19-percent share, followed by Wal-Mart with 15 percent, Best Buy with 13 percent, and Amazon with 6 percent.

The NPD Group, which reserves certain data for paying customers--like Apple, Wal-Mart, and others--and more general results for publication in the press, isn't taking ownership, but it's not exactly denying the numbers in the report either. NPD spokesman Lee Graham told CNET News.com he "can't comment on or confirm the information because all of that was based on a leaked memo from Apple."

Wal-Mart has long been the leader in global music sales, but Apple opening up a lead isn't a huge a surprise, as it's been on a roll lately. Most recently, the iTunes Store passed Best Buy to take up the second-place spot, according to an NPD report released in February.