Compatable with Boost Mobile???

No. ATT uses GSM while Boost Mobile uses CDMA and TDMA.

You can, however, use it with T-Mobile or Straighttalk as long as you get the Network Unlock Code for the phone. Without the code, the phone will be locked to the ATT network only. You can either pay a website to get you the code, or if you have had the phone long enough you can call ATT tech support and request the code from them for free.