This functionality is tremendously useful for all Pocket PC devices made before Windows Mobile 2003 Second Edition. But, with the advent of higher graphics and rotating landscape/portait screens, this application is no longer robust for future devices. (The emulation can still function, but the PC screen is grainy and sometimes unreadable.)
Possibly due to this fact, the Remote Display application has been removed from the Microsoft PocketPC Power Toys page; it can still be found on some mirror sites with some deep searching.
The advent of the new graphics has been a double-edged sword, in that Support, Documentation and Presentation of these new technologies has been hindered by a vacuum of robust emulation displays.