I have two Nextel i580s that use sim cards, will my T-Mobile sim cards work with the Nextel phones?

There's a message that shows up on the Nextel phone when I put in the T-Mobile sim card that says,"Enter Special Code Now." What code would I need to put in in order the phone to work?

I have two Nextel i580s that use sim cards, will my T-Mobile sim cards work with the Nextel phones?
Soz the only way is to change phone or keep on nextel.
Reply:They're not going to work no matter what code you put in there, they use different technology on those two networks. T-Mobile is a GSM provider similar in fashion to AT%26amp;T, and Nextel is an I-den network. The two are not compatible.