subsidized=locked
unsubsidized=unlocked
Its' a GSM phone -- you can swap out the SIM card.
By "locked" it means you're locked in to a contract and can't bail out without an ETF.
Wrong answer. Locked means that the phone will only accept SIM from the carrier it it "locked" to. You must SIM unlock a phone to use any carrier. The N1 comes SIM unlocked out of the box, both subsidized and unsubsidized.
I agree with jesseshangout. If your mobile is unlocked you can contact your service provider or try online sites. I unlocked my mobile at prounlocking.com within minutes.