Hi Tim,
All of your the forms you have built in ArcPad 8 will work just fine in ArcPad 10!!
The Python support that has been added in ArcPad 10.0.3 allows you to use Python scripting for a Windows install of ArcPad (not Windows Mobile), but VBScript and JScript support are still there and are able to be used in both the Windows and Windows Mobile environments...
I hope this answers your question!!
Hannah Ferrier
Mobile GIS Specialist
Maptel