A while ago i went into my local apple store, whilst i was in there i had a chat with one of the sales reps who told me about an application where you can put some sort of password or code on the phone, so that if; god forbid, your iphone were to get stolen, you can block your iphone from use and wipe any data stored on it, without even having your phone with you.
I never got round to finding this app at the time, & have now forgotten the name of it..