It was straight forward for me.
I installed OS X, but had turned off Bluetooth in XP before I made the switch. That meant Bluetooth wasn't available in OS X. Also my SD HC adapter was not detected for some reason. Maybe because I had not used it before I installed OS X?
Last night I simply booted up using the supplied Win XP CD via the Dell Boot selector (press 0 at startup and choose CD DVD/RW) and reinstalled it. No problems. Just a little messing around afterwards as not all of the drivers are installed with XP so you need to run them from the Dell Drivers DVD that came with the mini9.
All up it took me about 60-90 minutes.
Tonight I'll go back to OS X and hopefully my Bluetooth and SD HC adpater with be recognised