If you are wanting to sell, to make the most money would be to list them individually on eBay - it is a lot of work but in the end can make the most profit.
To sell it as a whole - it would really depend on what is in the collection, and possible your location. If the cans are nice enough, there will be collectors who will pay for the cans & shipping - with a large collection, shipping adds up quickly.... leaving collectors wanting to spend less money of the can themselves.
If you happen to live near a collector, possible they could offer you money for the collection. For example, I live in east central illinois - and if the price is right, I buy collections from basiclly anyone in Illinois or Indiana (or maybe a bit further if I don't tell my wife.) - as I could possible drive there, and if not *hugh*, fit the collection in my car - otherwise, I may be able to borrow a van to pick them up.
I've collected cans for many years - run the (very outdated) popcan.org website. I've once wanted forums & a site like this - glad to see this one here, and plan to support it as much as possible. ***UPDATE*** I May be trading soon! My Collection will finally have a home!