how to unlock a sprint blackberry 9670 for use with boost mobile?

[Joshua]

i bought the phone 3 months ago from sprint and im all set with there service so i canceled the contract and paid them the money now i have a real expensive paper weight .what i want to do is be able to unlock/flash my phone so i can use it with boost .ive looked on line about how to di it and they said to install a program titled (GETSPC) well i down loaded it to my phone and it will not do any thing saying can not open file wtf what do i do please help me