I used to develop against some RFID hardware that caused some problems. I had to be sure to keep the antenna pretty far away from my TouchStream or the mouse pointer would dance and I would get random characters on the screen. I also noticed the buzzing in the headphones. I am not sure what to do about it, other than try to keep some distance between your phone and your keyboard. Typing inside a ferrite box would probably do the trick, but I doubt it would be fun or cheap.