Here's proper "marketing" for this:
ANONYMOUS T-MOBILE PREPAID PHONE SERVICE
T-Mobile offers the $30/month prepaid plan called 1500 Talk & Text http://www.t-mobile.com/shop/plans/prepaid-plans.aspx
Includes: 1500 units (combination of your minutes and texts) plus 30 MB Data included
You can purchase reloadable minutes in $10 increments. These can be purchased with bitcoins, dollar for dollar, using the exchange rate shown on BitcoinWatch.com.
For example to buy 3 X $10 prepaid refills ($30 worth) and the exchange rate is at parity, you pay 30 BTCs.Introductory special: While supplies last, $10 prepaid refills are being sold for 8 BTC. Your 1.0 BTCs buys $1.25 worth of T-mobile prepaid dollars.
I have purchased my first month of refills (3 separate $10 transactions) with no problems, even after learning the seller's storied history. The seller provides the refill code before I make payment with bitcoins so I that can verify the refill was accepted by T-Mobile.