Probably your best bet to sell them is craigslist. If you're in a college town (Jacksonville, Gainesville, Madison, Tallahassee, Pensacola) they'd make great transportation for students.

As far as pricing is concerned, neither is particularly collectible and the Schwinn's frame is common carbon steel (I suspect the Columbia frame is the same) making it pretty heavy by today's standards. I'd guess they'll sell for $50 to $100 each.