i want to have a sidekick phone. does it work on any network or only Tmobil?

i think that only t-mobile carries that phone...

Hi if the sidekick mobile is locked to t-mobile then it wont accept any other GSM sim until you unlock it ...You can easily unlock your phone through online providers like TheUnlockSpot.com here they are rendering network unlock code for all mobile models at reliable cost .You first check that whether the code is available for your mobile model ,country and network provider .If yes then pay for it and unlock your phone then freely use it with any GSM sim ....