if you buy the HTC desire Z on vodafone pay as you go do you have unlock it to use a...

...o2 sim card? o2 pay as you go sim card

Yes if you will buy a HTC DESIRE Z in Vodafone network locked condition,you need to unlock it to use with other GSM network sim card like O2.Without unlocking you cannot use other network sim card in it.Visit the site Unlock-zone.com get unlock code at low cost and unlock from network lock.