There are two Adsense for Maps products provided by Google to monetize Google Maps API application:
Advertising using the GoogleBar

Adsense using the GoogleBar
var map;
if (GBrowserIsCompatible()) {
var mapOptions = {
googleBarOptions : {
style : 'new',
adsOptions: {
client: 'your-publisher-id',
channel: 'your-ads-channel-id',
adsafe: 'high',
language: 'en'
}
}
}
map = new GMap2(document.getElementById('map'), mapOptions);
map.setCenter(new GLatLng(27.6648274, -81.5157535), 12);
map.setUIToDefault();
map.enableGoogleBar();
}
Line 06: adsense options:
Line 07: your adsense publisher ID
Line 08: your adsense for search channel (optional)
Line 09: ad safety level (optional)
Line 10: language in which to display results
Advertising using the Maps Ad Unit

Adsense using Maps Ad Unit
var adsManagerOptions = {
maxAdsOnMap : 2,
style: 'your-ads-unit',
channel: 'your-ads-channel-id'
};
var publisherID = 'your-publisher-ID';
adsManager = new GAdsManager(map, publisherID, adsManagerOptions);
adsManager.enable();
Line 01: specify ads options
Line 02: maximum number of ads
Line 03: your ads unit
Line 04: your ads channel id
Line 07: specify your publisher id
Line 09: construct the GAdsManager object
Line 10: enable ads