Does anyone know if there is a software app for aiding study, like a flash card system, or a quiz where a quiz file can be imported and your knowledge tested.
There are a couple flash card programs. MyFlashCards works in OPIE. Z Flash is another. There are several for learning Japanese, but I'm not sure if any can be used for other purposes. I'm not sure about a quiz program that allows you to import quiz files. A lot of the quiz programs I've seen on Windows & Macs are proprietary commercial products I'm not familiar with what is available in Linux, but there are some education-oriented sites for Linux users that might have some programs of interest that can be compiled for the Z (see my response to your next question). You might want to look at
seul.org.
Is it generally possible for apps for Linux desktops to be re-compiled for the zaurus, I'm thinking the only spanner in the works would be the the VGA screen. Am i right in thinking that if it works in VGA on the desktop it will work on the Zaurus.
Yes, many Linux desktop apps can run on the Zaurus if you use one of the X Window based distros/ROMs such as OZ+GPE or PDAXROM, X/QT on the Sharp ROM or Cacko. I'm not sure if every VGA app in a Linux desktop system can be made to work on the Zaurus as it may depend on what other libraries and apps a program depends on. So, some VGA apps may not work. There are quite a few apps from the Linux desktop already compiled to run on the Z if you use one of the above distros/ROMs, so you may not even need to do more than install the package from the relevant feeds.
The Zaurus screen from what i read is respected as probably the best of all pdas, does anyone therefore use it for developement work when on the road?
Many do. There are a bunch of text editors, but also some IDEs that can be used to program. You should check out this site's the "Everything Development" forum and its numerous subfora for more details.