You can export all of the contacts on your phone to your microSD card, as vCard files. You can then copy this file to a computer or another device that is compatible with this format, such as an address book application.
Insert a microSD card into your phone and mount it (in the Storage settings menu).
Open the Contacts application.
Tap (or press) the Menu Key > Import/Export.
Tap Export to SD card.
Tap the contacts you want to export to the microSD card. To export all contacts, tap Select all in the top left corner of the screen.
Tap Export and then Yes to confirm.
Enter the file name and tap OK.