It has been rumored before that it was only a question of time before Apple would stop offering exclusive deals on the iPhone, and in the UK it has been talk about both T-Mobile and Orange to get their iPhone share of the market as well in the near future. According to TheRegister it now looks like things are about to happen as T-Mobile is offering iPhone 3G to top spending customers in the UK to avoid them shifting over to O2.
We have several times argued that Apple would change their mind on the network exclusivity, that it was used as a successful market entry strategy, securing premium income through giving networks exclusive deals. Now the iPhone economy is moving into scale, and Apple is realizing that the market demand is much bigger than what one network can cover in some of the main markets, like the US and the UK.
Now it is important to remember that these are not confirmed facts, and T-Mobile supplying top UK customers with endorsed iPhone 3G does not mean it is with the backing of Apple, at least not yet.
Hopefully it will just be a question of time before Apple makes the iPhone on multiple network carriers official.