Yo, no you cant.
Untrue. You can use redsn0w to install the iPad 6.15 baseband and unlock I believe.
I think unlocking allows you to use any network etc.
Jailbreaking allows you install cracked apps etc.-
I'm so confused tho. I hear different things all the time. The iphone 4 can/can't be unlocked, baseband 03.10.01 can/can't be unlocked etc.