So my questions are
a) can you buy an N95 with the proper Nokia firmware on it in NZ (i.e. parallel imported)
b) do you need to? Is it true Vodafone prohibits use of Voip?
Thanks in advance
The stock standard Vodafone firmware supports VoIP. Early Live! branded N95 versions in the UK had this cripped but this has never been the case here.
Firstly up you can't use the VoIP client for Skype. Skype uses a closed propretory protocol but the phone uses a SIP stack which is basically the defacto standard for VoIP. They are not compatible.
Vodafone also have nothing to do with billing because it's nothing to do with them, any VoIP calls you made are billed by your VoIP provider, not Vodafone.
Vodafone's claims that "VoIP is prohibited" seems to be regarded as simply a claim that they don't support VoIP because they can't guarantee any QoS over their network. Most people using VoIP on the N95 (or other Nokia phones with a SIP stack) are using this over WiFi. VoIP does work over 3G but there is no guarantee when it comes to call quality and your milage does vary. While stationary on a site that doesn't have a lot of other data users it works perfectly, try it while mobile and your milage will vary. If you do want VoIP over 3G you certainly need to be using G.729 as it's a lot lower bandwidth.