Are you looking for an inexpensive mobile app to track pitch counts or record bullpen sessions?
(source: Hachisoft Corporation)
$1.99 at the App Store
I watched a short iPad demo of the Baseball Bullpen app that looked interesting. I don't think the speed indicator would be very accurate (depending on your reaction time), but the pitch type and location tracking would be handy.
View the Baseball Bullpen demo by Paul Reddick