Wireless providers need to change their business model
Nothing quite irritates me like wireless companies disabling certain features on cell phones in order to reap a bigger profit. Case in point: AT&T and Apple might not permit Google Voice to work on the iPhone because it would allow for free SMS services that would cut into texting profits for AT&T. For a similar reason, the best feature of Skype was disabled on the iPhone and, to the best of my knowledge, Windows Mobile.
I hate to break this to you wireless carriers, but you can’t stop progress. Eventually, some new telecom is going to offer data-only connectivity for less and with that single connection the user will still get voice and texting at no extra charge. Your best best would be to simply offer such a thing now. Will you? Of course not. You need to nickel and dime us to death in order to make your profit.
But eventually, someone will be able to break into the field by exploiting the shortcomings of the current business model. You will cry "foul". You will prepare your attack lawyers. But in the end, the consumer will win and pay less for more services that would likely be cheaper for you in the first place. Any issues regarding the reliability of voice calls over a data network will be resolved and your only choice will be to charge a monthly flat fee for all services that an iPhone (or any cellular phone) can possibly provide.
In the meanwhile, enjoy your little victories. Over the long run, they will be forgotten.