Actively using Foursquare yourself? Why not creating a map like this for your site? It's free and licensed under a Creative Commons license.
All you need is a server running PHP 5, which is probably the case with most servers. Download the sources below, add your Foursquare feed and you're done.
The map won't just show your most recent check-ins, it'll also silently update every few minutes and check for new. Your audience will always know where to meet you.
Enjoy and have fun...