Catalina Island Maps
This map from the Catalina Conservancy shows the major roads, trails and campgrounds. It's good for getting oriented to the island's layout.
Map of Avalon (Online)
You can zoom in and scroll around this online map, which shows many points of interest.
Map of Avalon (download)
Shows points of interest, restaurants and the like. This is the map that you'll see at locations all over town, but you can't view it online. You'll have to download it (in .pdf format) and print out.