Will a nextel sim work in a boost mobile phone?

i dont want to resign for 2 years with nextel, but i need a new phone. if i buy a boost mobile phone ( looking at the i9 Stature) will i just be able to put in my nextel sim and it work? I have heard it will but it needs to be unlocked first, what does that mean?|||Ok here is the deal...Boost Mobile is Nextel's prepaid phone service. Even though they are pretty much the same company unfornately you still can't interchange the sim cards because of Nextel being programmed as a contract service and Boost is programmed as a prepaid service. Unlocking the phone has nothing to do with the sim card but with the Esn or Meid number which is found on the sticker underneath your battery on your phone. Some retailers will take that number and unlock it so that you can use that phone on any carrier that you wish but you have to find a company that will do that. Without the phone being unlocked you are stuck having to use the phone on the given carrier it belongs to. I hope this has helped and God Bless!