AT&T today officially confirmed what so many had expected for some time now: the carrier will be throttling select users' unlimited data plans. The move, which takes effect on October 1st, is a response to a "serious wireless spectrum crunch," according to a message issued today. The changes will not affect most customers, according to the company, primarily targeting those who fall within the top five percent of heavy users in a given billing cycle. Once the new period begins, speeds will be restored. Even with this new plan in place, however, the company says that the spectrum problems still won't be resolved -- it does have a simple solution, however, explaining that "nothing short of completing the T-Mobile merger will provide additional spectrum capacity to address these near term challenges." Full text after the break.