T-Mobile is offering new micro-SIM cards designed for the iPhone 4.
That means you can run your iPhone 4 on T-Mobile, no sweat.
Since T-Mobile doesn’t sell the iPhone 4, you’ll have to buy an unlocked GSM device from Apple first.
Here’s the announcement from T-Mobile’s website:
Already have a GSM phone or iPhone that you need to activate—or have an unlocked GSM phone you want to use on the T-Mobile network? Just get a Micro SIM card and choose a plan. Slip the ready-to-use Micro SIM Card into your phone and you’re ready to go.
If you want to take advantage of T-Mobile’s cheaper service and unlimited data plans on your iPhone 4, now’s the time to do it.