The Begeron's mural is on the door (you can only see it when it's pulled down) of Bergeron's Books at 375 15th Street in Downtown. Above it, the awning says "Read Speculative Fiction." This mural actually predates Begeron's- when it originally was painted, it said "Love Oakland Group" at the top. It was painted by one of their members, Free Rolando.
There are also murals covering the walls inside.