Now this is something that every country on Earth should stand up and take notice of... the Department of Telecommunications of Chile just implemented a new rule that requires all mobile phones that are sold in the country to be unlocked. Besides the fact that it makes modding devices much easier in Chile, it also means that you can take any phone and make it work with any carrier within that country.
In fact, the Chilean government has even taken it to the next level, and the rule is pseudo-retroactive. It is worded such that any locked mobile phone purchased prior to the January 16 date is to be unlocked by the carrier free of charge. They implemented a formal procedure to make the process easier for customers. The carriers will be required to put up a webpage where the user can enter the IEMI, device model, and some other info for security purposes, and the phones can then be unlocked by the carrier. Reportedly, they are even working towards creating rules that would make all numbers portable as well.
It would be fantastic if something like this were passed in the United States, but what do you wanna bet that the various carriers would spend millions lobbying Congress to stop it from happening...