Amazon made another major push today to go head to head with iTunes, launching an MP3 store that's optimized specifically for use on Apple's devices. Many single-song downloads from Amazon's Cloud Player app—which currently boasts a catalog of 22 million songs—are available for 69 cents, nearly 30 cents less than iTunes' lowest-priced tracks. Any songs purchased from the app are saved directly to the customers' Cloud Player library, and can then be downloaded to any iPhone, iPod touch, iPad, or Kindle Fire.