FUNimation just made three of their series available through their new iTunes store. All 24 episodes of Desert Punk, all 26 episodes of Samurai 7, and 20 out of 24 episodes of Speedgrapher are available currently(the other 4 will be available on March 6 when the DVD is released). 

All the episodes are English language and 640×360 pixels (16:9 widescreen).