INFO: Sorry, this stopped working due to errors in foursquare’s KML feed (Info). Will update info if a soultion is found.
— Warning: the following requires you to share your private data to the public. It me be illegal in your country and your queen may not be amused. You have been warned.
I added my foursquare checkins to google maps on my blog
Here’s how it works:
you need your foursquare KML feed: http://foursquare.com/feeds/ (RSS Feeds do not provide location data on foursquare)
A Google Maps API key. Grab one here: http://code.google.com/apis/maps/signup.html
A Google spreadsheet with your checkins from . Get a copy of mine: http://spreadsheets.google.com/ccc?key=0AkJULjdkpbJrdF9GcWhBSjctT0xnRlNFZi15SVgzLWc&hl=en
You need to tweak the spreadsheet to contain your 4sq KML feed adress in cell B2 and H2.
You need to share and publish your spreadsheet. See  on how to do that.
The tool “Create a map from a published Google Spreadsheet”: http://gmaps-samples.googlecode.com/svn/trunk/spreadsheetsmapwizard/makecustommap.htm
And you are ready to go. You can even tweak the resulting script code!
Have fun!Created: Fri 19 Feb