The fist addition is the possibility to use a link unit instead of direct ads. As you might know a link unit consists of links / topics related to the content of the page. After clicking a link Google will show a separate page with relevant ads. Note that as a publisher you will get paid for clicks on the ads on the separate page, you will not get money for clicks on the topics itself.
As Google mentions this could be a very nice addition to your map if you have limited space available but still want to monetize the map. By the way, the link units and the layout of the landing page where refreshed last year October by Google. With the refresh Google also decided to show a maximum of four topics in horizontal units and three topics in vertical units.
The second addition is that you can now customize the design of the Maps Ad Unit. So you can now set different colors for the background, border, link, text and the URL like you can do with ´regular´ ads within Google AdSense. This way you can match the design of the ads to the design of your own website.
There is a demo where you can test-drive the new features, the demo can be found here. “While the demo illustrates only a subset of the supported formats with a limited number of predefined styles and on-map positioning, you have much more creative freedom over your own ad unit.” Explains Google. If you are looking for more information about monetizing Google Maps see the developer documentation and the Maps API reference.
Of course you will need an Google AdSense account for this to work .