[skelsey]

Go here: http://prepaid-phones.t-mobile.com/sim-card. Check your device, and once you know which SIM type you need, click the "Add to Cart" under "Phone".

I literally just did this, so the timing of this post is nice. Even more nice is that they are waiving the $10 SIM card fee right now.

You buy the actual plan after you get the SIM and activate it. I don't know what they charge for activation, if at all.

[mortehu]

So it's not available to current T-Mobile customers unless you want to change your number, then?

[hayksaakian]

Move your number to Google voice

Then you can use your unlimited data for calls (if I'm not mistaken)

[thaumasiotes]

I used switching to that t-mobile plan as an opportunity to set up google voice. At least now I can cover future number changes.

[lotyrin]

Port out to another prepaid, then back in.