I am thinking of getting... pfffft, who am I kidding... I am going to get an N900 when it is launched and will probably buy it direct from Play or Nokia - rather than wait for my contract upgrade with o2. If I do get an unbranded unit, how easy will it be it to get the o2 settings on to it (for web, SMS, etc.)

These settings come on your SIM card and the phone should change automatically depending which card you put in.