T-Mobile is planning to announce an unlimited voice and data plan to compete with Verizon and AT&T, both of which have already unveiled similar plans. The move would bring T-Mobile up to speed by offering its customers unlimited calling alongside limitless text messaging, something iPhone owners have access to starting this Friday from AT&T — Apple’s exclusive iPhone service provider in the U.S. T-Mobile’s alleged plan will cost $100 per month for unlimited minutes, long distance, and roaming in the U.S.