Found that out today. Kinda sucks. Is that a hardware issue or a software issue? Right now I have my airport extreme broadcasting in 5ghz for my MBP and my iPad. They work just fine. I have my airport express set up and broadcasting in the old b/g compatible world for other devices like my Roku box, older iMac (and I guess new iPhone). So if I go to my airport extreme settings and chose 802.11n (just not the 5 ghz - see pic below) will it be faster, and thus my iphone 4 will work with it, or should I just allow it to use the regular wireless broadcasting from my airport express.