Seems the Offical IPCC files for vodafone NZ have been released..
http://appldnld.apple.com.edgesuite.net/content.info.apple.com/iPhone/CarrierBundles/061-6562.20090612.AvshB/Vodafone_nz.ipcc
3 APNs
www.iphone-vodafone.net.nz (type-mask = 1 (data))
live.vodafone.com (type-mask = 4 (mms))
www.vodafone.net.nz (type-mask = 48 (32+16))
Its not known 100% yet what the 32+16 type masks are for yet
16 = ??
32 = ??
8 was thought to be the APN for tethering but none of the have bit 8 enabled) only 1,4,16,32
so maybe it the APN used for location services?
Someone who has a 3G phone may want to install and see what comes out?
Can someone from vodafone say if tethering wil be enabled so it will help guess what the type-masks bits mean??