Nextel sims in a blackberry?

will i twork. some people told me it will work but if nextel finds out blackberry will fine you and its not cheap. then i called nextel and they said it wont even work. then i talked to a buddy of mine he said it worked fine but im not sure how much of th ephone will work with the sim can i get text messages and stuff over the phoen without using a blackberry plan?

so no one ever switched over theresim card to a blackberry?

Dunno how it is with nextel.. Im on cingular and I just put my regular SIM in the Blackberry and I was able to Text and Talk with my regular voice plan and then i just called up the customer service and had them cancel my old media package and added there Blackberry Data plan to my account so I could use the web browser and use there email services..