Hard to say for sure. When I used an unlocked Treo (several of them, in fact) on AT&T I had to configure them for AT&T's data service. I had to set up internet/email, MMS, and even SMS. Other devices auto-configure based on the SIM card. Some Nokia phones can get a text message that contains the settings in the form of a link. Just opening the message activates the link and the user only has to say "yes" to importing the settings. So it all depends on the N8.