Although there have been Pocket PC's with VGA (640 x 480 resolution) screens for a number of years it was not possible to use the true capabilities of this resolution without the use of third party utility software. Without such software the nice screen on your handheld was mainly "pixel-doubling" to make images look nice but not putting anymore real information on the screen. The benefit of using the screens full potential would be, for example, browsing the web without endless scrolling or viewing Excel sheets, etc. The disadvantage for some is that it makes the text very small - similar to hi-resolution mobile phone screens.
SE_VGA and ozVGA were popular software for devices running Microsoft's earlier Pocket PC 2003 operating software. Both pieces of software were freeware and reasonably simple to use. However with Windows Mobile 5 niether of these utilities yet work. Well, at least, not straight out of the box.
Do not dismay, however, because there are two solutions:
The first is an absolute Swiss Army Knife of a video package called Nyditot Virtual Display (NVD). It costs US $19.95 but there is nothing that it won't do when it comes to altering the video resolution of your Pocket PC
More information
hereThe second option requires a little technical dexterity to set it up but it's FREE

It's based on the original ozVGA software and requires some additional files added to the system folder of your Pocket PC and then if all's well you're off. ozVGA has less features than NVD but does the job.
More information
hereNeedless to say with both applications make sure that you've backed up your device BEFORE you try out the software.
Also bear in mind that not all PPC applications run in "Real VGA" mode and some might even crash altogether so proceed with care.
Good luck!