merryperson

I need to calculate the distance between postcodes to find out how far people travel.I have obtained details such as latitude and longtitude for each postcode and know it is possible to do this but how? example of the information held postcode x (in metres)y latitude longitude AB10 392900 804900 57.135 -2.117 AB14 383600 801100 57.101 -2.27 EX35 272400 148800 51.224 -3.828 EX36 274300 125700 51.016 -3.792 Anyone have any ideas? Thanks dave