And speaking of Virgin Mobile, the only MVNO left standing is now joining the major wireless carriers in offering a flat-rate plan, according to MediaPost: "Starting July 1, it will offer an unlimited calling plan for $80 a month with no annual contract. Unlimited text and messaging is thrown in for another $10 a month."

Astute observers will note that Virgin's plan costs $20 per month less than the four major carriers (Verizon, Sprint, T-Mobile, and AT&T) are charging for similar services. There's one major difference here, though: Virgin Mobile is also a pre-paid service, while the other ones all require a two-year contract.