If you want real gps/gsm combo, take a look at nokia 5140 with gps covers. Covers work as gps antenna and they don't need cel service. Another option is benefon esc! (or other benefon gps/gsm models) which is really a fully featured gps equipped with phone.
Motorola i530 uses agps system which needs cel network to work. There may be network present although your phone shows no service.
Nokia: http://www.nokia.com/nokia/0,,53751,00.html
Benefon: http://benefon.com/products/esc/