This seems like a novel use for a Pocket PC. I could totally see using secondary displays for things like IM, the same away Adobe Premiere can render video to a TV-screen while you work on the timeline. Finally, a screen for my pr0n while at work 
SideWindow turns your Pocket PC into a secondary display – Engadget – www.engadget.com
The app installs on XP, and tricks Windows into treating the Pocket PC as an additional screen. You can drag any window over to your new mini-monitor, allowing you to use it as, say, an IM console, image viewer, or sticky note display, without installing any software on the PDA.