For your internet and MMS settings for your Nokia Lumia see below-
1. Press arrow right to access the
main menu. Press Settings. Press
mobile network. Press add apn.
2. Enter APN Press the field below
APN. Key in : giffgaff.com
3. Enter username Press the field
below Username and key in : giffgaff
4. Enter password Press the field
below Password and key in :
5. Save and exit Press the confirm
icon. Press the Home key to return
to standby mode.
For a full guide to these settings please click on the link here. http://j.mp/giffgafflumia
I hope this helps. Any issues during setup please let us know. 🙂