Unlock codes. i have a motorola i870, and a blackberry 7520, both from nextel, i like to unlock

Question

i have a motorola i870, and a blackberry 7520, both from nextel, i like to unlock them to use my sim card from my motorola ic902 (sprint/nextel), if swap the sim from ic902 with i870 only radio(walkie talkie) works but nothing else.              please heeeeeeelllllllllpppppppppppp!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!