http://www.macrumors.com/2009/07/13/apple-blocking-push-notifications-on-unlocked-iphones/
Does this effect the XT network? I assume that from the lack of problems people are claiming here, it isn't actually a problem? WOuld be good to clarify however, as push notifications were something that I was highly looking forward too, and I would prefer not to have to stick with Vodafone.