Just ordered mine via BEST BUY through this link,which is active once again:
Best Buy Posts T-Mobile HTC One Pre-Order For $249 | TmoNewsTmoNews
Just click on the BEST BUY link & order,whether on or off-contract,but,it's a classic plan w/a 2yr agreement.
ATM,this appears to be the only way to access BEST BUY & order the T-MOBILE branded HTC ONE.
Shipping status pending with an APRIL 24 ETA.