Can't find Airplay Icon

I just purchased the Apple TV and hooked it up easily to my television. I do have internet access and am able to access my iTune libary. Problem is I can't not seem to stream a movie from my iPad (which is only 2 months old) or my iphone 4s. Neither device has the icon for airplay on it. I do have Airplay selected as ON with the Apple tv. Just on a side note, I am using the airport express for wireless connectivty. Everything seems to work perfectly except for the inablility to mirror movies with my TV and iPad. Any suggestions?