mrbean,
This document lists which National Instruments products were tested with XP Pro. CVI versions 6.0 and higher are supported by XP Pro.
As far as what else you may want to look out for, the most common issues when switching operating systems are related to ActiveX controls and servers. If the ActiveX server or control on your development machine is a different version than that of your deployment computers, the code may need to be rebuilt for the target machine.
Scott Y
NI