Ring your service provider immediately and they will bar the IMEI (the identificication number for your phone, it's unique). THat means regardless of the SIM they put into your phone, it will not work, leaving it useless to them. The only chance you have of getting it back is if someone hands it in. Phone locations will not be traced because you lost your phone unfortuantely. The only time a location of a handset is traced, is in the case of Federal Authorities trying to trace a criminal etc., for more then stealing a mobile phone.EDIT: To clear up the answer above me - even if your phone is under warranty, it is not covered, because YOU lost the phone sorry. It is only covered against manufacturing errors/faults that show in the first 12 months unless otherwise stated. Also, as the first reply says, you can have the SIM with your mobile number (that you assumingly lost in your lost handset) replaced. They can send a SIM replacement to you, at your cost. Again, it isnt there responsibility that you lost the phone or it was stolen. It's all an easy fix, but a pain in the ass nevertheless. Good luck