The Amazon MP3 store is now optimized for iOS devices, according to an announcement from the company today. That means that for the first time ever, you can purchase music from Amazon's catalog — now 22 million songs deep — directly from an iPhone or iPod touch. You'll need to use mobile Safari to do so, but Amazon says its iOS store has been designed using HTML5 and should offer customers everything they've come to expect: recommendations, user ratings, and discounted $5 albums / $0.69 songs are all offered via the new site. Additionally, purchases will be available for immediate streaming and download from within Amazon's Cloud Player iOS app. It's still not quite as seamless as Apple's integrated iTunes solution, but things just got much easier for those who've taken Amazon's side in the digital ecosystem war.