Can a sprint phone be connected to boost mobile?

No you cant!

Yes you can and I have done it didn't even have to flash my phone to there firmware. Wow people I swear it's one person pissed because they can't figure it out or something. Same first answer different phones. They really need to find out who is and who isn't "experts". I mean if your trying to break out of contract just don't if your doing it because your broke that's the phone you have and that's your only option then yes just call boost give them the meid# on it. Now some old body phones are gsm with SIM card. If that's the case then no you cant switch.