About the only theatrical uses I could imagine for a pocket PC would be for using wireless remote focus software (ETC makes this I belive), or acrobat reader for reading PDF equipment manuals.
I would not run any sound cues off a pocket PC because it's internal sound card will most likely not sound nearly as good as a normal CD or Minidisc deck. I don't know of any sound cue playback software for the pocket PC, but if you must, you could feed it's headphone out through a pair of DI boxes as I've done before to play some music during a rehersal through the house on my friend's pocket PC.
I also keep various little task oriented calculators on mine. Just reset the thing as it got trashed again, don't have the names of the ones I kept on there. Have to refind them on the internet, unfortunately.
I am going to be using my Acer Pocket PC on Wednesday to help me fault find on a new audio system installed in a new school theater I am involved with. A microphone on stage wasn't working and because it has a number of patch panels between the stage and the booth I need a sound source. So I downloaded a tone generator and will feed a mono signal from this via a battery powered DI box through the signal path starting at the desk working to the stage. This way I won't need another person to help me.
Don't bother. I have yet to see a Pocket PC or Palm based program that does transfer functions, and if you want to accurately calibrate and analyze your system, that is what you need, NOT a plain RTA.
This is what a program like Smaart or SpectraFoo does on a laptop. The difference is that these programs take time into account and allow you to distinguish between what's coming out of the speakers, background noise, reflections, etc. They also have impulse tools to help you line up delay systems, in addition to RTAs (which do have their uses, just NOT for system tuning).
Not sure why you would lug around as oscilloscope; that is useful for troubleshooting hardware, but not for system tuning.