Your post is little ambigious. no worries If you are referring to 3G internet, then please find the following.
Go to Settings>General>Network> Cellular Data Network
I guess you might have something related with o2, delete the ones and add the following.
APN - giffgaff.com
Username - giffgaff
Password - password
MMSC - http://mmsc.mediamessaging.co.uk:8002
MMS Proxy - 220.127.116.11:8080
Max message size - 307200
MMS UA Prof URL - [blank]
That should take care of it,
GiffGaff does not offer automatic settings for iPhone at the moment.. May be in the near future.
Make sure you have credit or a active goodybag then please follow this guideIphone Internet SettingsOn your iPhone go to: Settings>General>Network>Cellular Data NetworkThen enter:Cellular DataAPN: giffgaff.comUsername: giffgaffPassword: password Visual Voicemailleave blank as giffgaff do not provide itMMSAPN: giffgaff.comUsername: giffgaffPassword: passwordMMSC: http://mmsc.mediamessaging.co.uk:8002MMS proxy: 18.104.22.168:8080MMS Max Message Size: 307200MMS UA Prof URL: leave blankrestart the iPhone to activate the settingshttp://community.giffgaff.com/t5/Learn-giffgaff-Top-Tips/How-to-giffgaff-an-iPhone/td-p/1807If you get stuck check this guide > ( Video Guide >> http://www.youtube.com/watch?v=7Up7V4nW8Go ) Easy Option For WiFi 1) Insert your giffgaff SIM 2) connect to wifi 3) open safari and go to http://invalid.name/giffgaff (might take a while too load so just let it do it's thing)4) a notification comes up and asks you to accept a profile5) press install and then Install now to confirm
More help if needed http://community.giffgaff.com/t5/Learn-giffgaff-Top-Tips/Newbie-Quick-Internet-Guide/td-p/2066679