how can i get my nextel simcard working in a tmobile phone?

hi i have a nextel phone and i cant stand it with the text messages. but i also have a tmobile phone. i know people that have like tmobile planes with a cingular phone vise versa. so i was swondering how can i get my nextel Motorola i700 simcard working in my tmobiles Samsung SGH T509S? i know theres a way to hack the phones i guess help please neeed details in answersif possible.