the author of this app says:
PADD makes your Pocket PC look like a Star Trek device. It has great sounds, Star Trekky graphics and even speaks in the computer's voice.
As far as I can tell, it doesn't answer to voice commands, synthesize food or give you a complete analytical breakdown of foreign substances. And even though I tried to talk to my friend in Australia through it, no one answered, so I'm pretty sure it doesn't work as a communicator.
Still, it's a pretty nifty program to have on your Pocket PC to show your true affection for Star Trek. Make it your preferred launcher, and you'll see what I mean.