Pretty much anywhere that sells maps: drugstore, gas station, bookstore or you can order from www.mapart.com

Perlys maps are good too. You can check them out at the www.randmcnally.com

Streetwise makes a downtown laminated map. www.streetwise.com

Cheapes though is the city bike map you can grab for free at many bikeshops.

<<edit beaten by Kergin >>