Reading Writing Preferences

[Nick Heppleston]

Hello All, Question relating to reading writing prefs through XUL 
widgets: How the hell do i do it??

I've already identified the following XUL attributes:

pref, preftype, prefstring, and prefattribute

but how do i use them, what values can they hold etc - does anyone have 
any documentation/can anyone point me in the correct direction?

Thanks for your help,

Nick