Checkin Mania is a Google Maps mashup to track who is checking in around you using FourSquare, Gowalla, Brightkite and Twitter.
To browse a location you can use the search facility or you can just click on the map. The map will then display all the venues around you and show you who are the top users of that venue with the popular location based social media apps.
It is now possible to add a Chekin Mania map gadget to your own website or to your Google home page. You can adjust the height and width of the Checkin Mania gadget, you can also set a default location and select the services you want displayed (Foursquare, Gowalla, BrightKite or Twitter).