LG Voyager VX-10000

I got the Voyager just before the BB Curve 8330 came out. I should have waited and got the Curve.

My question is, what do I have to do to my Voyager to be able to sell it on EBay or via some other means. Do I have to have it disconnected on my current contract and will Verizon allow me to do that? If I do have it disconnected, will I lose my current Verizon phone number even if I later purchase a Curve and have it activated through Verizon? Will Verizon let me change phones like this on the same contract?

Probably some simple questions but I've never sold a cell phone so I want to make sure I do it right.

Thanks for any replies!