1. Visit your foursquare feeds page. Control-click (right click on PC) the KML link and copy it to your clipboard (don’t download it).
2. Visit Google Maps and paste the link you copied into the search box. Hit enter.
Optional Parameter: You can specify a ‘?count=25’ to pull down a different number of checkins from your history. if you are requesting the ICS format, ‘count’ is not used (your entire history is exported)
I’ve done a lot of traveling, both personal and for work over the last couple of years and thought it would be cool to visualize my travels. Here is a Google Map plotting my last 1,000 Foursquare checkins.