Cool Icons for Google Maps, courtesy of http://mapicons.nicolasmollet.com/

To include any of these map markers in your Google Map, right-click on the icon and select "Copy Image Address" or "Copy Image Location" (the text might be slightly different depending on the browser you're using). Then, when you're editing your map, select the marker you want to change. You should see the dialog box with the marker title, marker icon, and description. Click on the marker icon and click on the "Add an Icon" link. Paste the URL of the icon you copied into the dialog box, and hit Enter. The marker should now be changed. Save the map marker and you're done!

Even more markers: