I mentioned this is in a different thread too but FWIW I was able to change to the $50 U/L plan at a corporate store in the loop. I was out of contract so that may have been a factor but I didn't have to get a new phone or sign-up for a contract extension/easy-pay. I'm essentially still out of contract. The process was relatively straightforward and amicable (i think I had to ask twice).The test market special runs until August apparently.
T&C's look pretty standard from what I can tell - this is a summary of the plan from the subscriber agreement.
FEATURES:
Unlimited Talk and Text,$30 Monthly Charge, (UL data is +$20)
Unlimited Anytime Minutes,Unlimited Messaging,Nationwide
Long Distance Included,America - Roaming Included,Call
Waiting,Three-Way Calling,Voicemail,MRC is not NVP
discountable
ADD ONS:
Unltd 3G/4G Data & Annual Upg