Unlocking an Iphone 4S for Boost or Virgin Mobile?

[out_of_my_league]

I apologize if this is in the wrong category, I'm new and tried my best to match my problem with the categories. I searched before posting and didn't see anything, as well. I just need help lol. I'm not good with this type of stuff.

SO...
A little background..

I have a black berry curve on boost mobile's network. So there's no sim card. I could easily transfer my service over to Virgin Mobile if I needed too, though.

I know and understand that most iphones are made on GSM networks and can't be unlocked for CDMA networks. Got that part. My questions are:

What are the loop holes? I saw somewhere that if you have a sim card you can unlock any iphone and just insert it. Is that true?

Since Boost and VM are under Sprint's network, is Sprint considered a CDMA network? Could I buy an unlocked Sprint phone and just use Boost?

Or what other suggestions you have for my dilemma. Or direct me to the right forum section if I'm in the right place lol.

 

[out_of_my_league]

haha well somebody could've told me I was on the wrong forum. I said I was new. Atleast I've found where I should've posted. So disregard this as people already have lol.