I have no affiliation with Milliesoft except i asked martin to create a feed for VNZ ondemand.

TunerFreeMCE is a Windows Media Center add-in for watching streaming internet TV programs on your PC and Media Center Extender. all through an easy to use Media Center interface.

http://www.milliesoft.co.uk/index.php?option=com_content&view=article&id=9:iplayer-mce&catid=1:software&Itemid=11

Thanks to Martin at MillieSoft who created a script to allow NZ content. Martin has advised depending on the demand he will also create feeds for all availiable on demand streaming sites in NZ ie: TV3 and C4. 

Download his latest version Windows 7 and once installed go to plugin and install the Nz plugin from there..

Cheers

Wazza