http://bit.ly/giffgaffandroid - Android guide
if you have wi-fi access, download the giffgaffAPN app from the Android Marketplace to set them up for you
or click here to download the giffgaff apn:https://market.android.com/search?q=giffgaff&c=apps
watch youtube giffgaff setup:http://www.youtube.com/watch?v=OQDm09iOZmc
If you can access WiFi go to Market (Google Play ) on your phone and search for giffgaf
Download and install SKINKERS
Accept 'delete conflicting APN's'
If no wifi a step by step guide with pics is here: