I don't know weather a Sidekick is able to be unlocked or not, but you can not use a T-Mobile Cellphone on MetroPCS. The Technology is not the same, so the phone will not work. You have to have a Sprint Branded phone, or another
CDMA phone, with Verizon being the exception (I Believe). T-Mobile is
GSM, and there for not able to be flashed or anything to work on MetroPCS.