Geoff Jones

If your iPhone contract has run out (or about to) then you can ask O2 to ‘unlock’ your iPhone. Once unlocked you can get a PAC code and transfer your existing number to T-Mobile.

Advantages

• The £10 a month unlimited internet and texts for life is a great deal for anyone, like me, who doesn’t make many voice calls.
• Since its pay as you go when you travel abroad you are no longer faced with a horrendous bill on your return. You can get one of their £5 roaming bundles easily by text whilst you are away.
• Topping up is a delight, they send a message when you are running low you can send a free text back with the last 4 digits of your previously registered credit card  the amount and three security digits, and away you go.
• The itemised billing is excellent, totally itemised bills to the last K of data transferred and instantly available on the web.
• 3G Coverage so far is awesome!

Disadvantages

• If your phone breaks and Apple replace it then according to the local Apple store it will be locked. Will O2 unlock a phone if you have no contract? When I asked at Apple they just said speak to O2 and yes O2 say speak to Apple. Maybe this issue will clear up as more iPhones get legally unlocked and Orange etc come to the market.
• At the moment  if I put the iPhone in Airplane mode the iPhone asks to be unlocked again by iTunes (to do this you have to remove the SIM, take it out of flight mode, reinsert SIM and then iTunes will unlock it).
• You get the silly Content Lock screen (in picture) if you access blogs 🙁
• The iPhone seems to eat the battery in 3G mode. I guess with O2 it never found a 3G mast!

Conclusion
Its great to have an always on internet, even in the depths of cafes and lecture theatres, so I’m sticking with T-Mobile until either I buy a Nexus or the latest toy from Apple.