According to MSNBC.com, it just got a little tougher to not shop at Wal-Mart. The mother-sized retail chain launched its film download service Tuesday, and unlike iTunes, the service has the backing of major studios, including Warner Bros, Walt Disney, Paramount, Sony, 20th Century Fox and Universal. (iTunes has Disney and Paramount.) Recent hits like The Devil Wears Prada and Superman Returns are among the 3,000 titles already available. The price is similar to a DVD, from $12.88 to $19.98.