I have one of these Targus keyboard. http://www.amazon.com/Targus-Blueto...N3WU/ref=sr_1_1?ie=UTF8&qid=1323090093&sr=8-1
But I gave tried my best to use the on board keyboard, so I don't have to carry stuff around. It is slow but my speed is getting better, the more you practice with it, the faster you become.