As an official sponsor for Major League Baseball (MLB), it was only natural that T-Mobile would offer some kind of promotional tie-in. The time has now arrived as the wireless provider is offering new and existing customers a free year of MLB.TV.
In order to take advantage of the promotion, you have to head to the sign up page using a supported wireless device while using T-Mobile service (don't connect via Wi-Fi). You'll then be required to create an account for MLB.com (which is free). After that, you'll be able to sign in and take advantage of the one year subscription.
Luckily, there will not be an auto-renew feature on the account, so after one year, the service will be automatically terminated. If you're interested, be sure to sign up quick, as the offer is only available from April 3rd through April 10th.