Here are some beer can related links.  The placement of these links on my website does not indicate an endorsement of the sites.  Hopefully you'll find one or two useful or entertaining.

Maryland 12 oz flat top composite list (UNDER CONSTRUCTION)
Rusty Bunch Chapter, BCCA 
BCCA (Brewery Collectibles Club of America) 
Canventory - Computerized system to catalog your collection 
The Merry Bocksters Chapter, BCCA

Friends and Fellow Collector's Sites, alphabetically ordered:

Baker, Dan: Beercansplus.com

Benbow, Mark: Rustycans.com

Gauger, Gary: Crowntainer Central

Gesland, Brent: Awesome Beer Can Finds
Karasek, Randy: Michigan Beer Cans
Menke, Matt: One Full Quart

Mobley, Bruce: Beer Bottle Library

Scoglietti, Dan: BeerCanMuseum.com