To utilize Foursquare to create pin map, just follow these instructions:
Login to your Foursquare profile from an internet browser
Now that you’re logged in, go to your feeds page. To find your feeds from your profile, you can click on “History”, then scroll down to the bottom of the page and find the RSS icon to access your feeds.
Copy the .kml feed (the second one) and paste it into the Google Maps search bar. Before you start the search, add “?count=5000″ to the end of the feed url (minus the quotes). You can edit this number to your liking; it just specifies the number of check-ins that will be displayed.
Now your pin map should be displayed. If you just wanted to view it for yourself, you’re done. If you want to display it, you can click “Link” in the upper-right corner and grab the HTML embed code. Then you can put it on a website, like I’ve done below.
That’s it! You now have a digitized pin map. Since Google Maps is pulling data from your check-in feed, a new pin will be automatically added to the map every time you check in. If you’re only interested in tracking your travels by city, you can simply check-in once at each place you visit. However, you might find yourself sucked in to Foursquare’s other features and start checking in everywhere. If you do, make sure you check your privacy settings to make sure you’re comfortable with them.