Foursquare has expanded the program for the Ambassador , foursquare experts who evangelize the service to their favorite places - see also http://foursquare.com/business/venues 

This from the foursquare blog...

It’s a pretty simple idea: if you’re passionate about foursquare and want to help get more Specials in your area, let us know. We’ll reach out to creative and excited evangelists who fill out the form, offering them a pack of foursquare Ambassador Cards (custom-printed with your name) to hand out to local businesses. The businesses get details about their foot traffic and loyal customers, and you and your fellow foursquare users will see more Specials at your favorite places.

To get started, sign up here to get an ambassador pack.

Source: Foursquare blog

For Business Owners:

To kick things off, business owners are encouraged to claim their venue. After that, a number of resources are made available including tools and tips to offer specials, venue statistics, and numerous tools and tips.

See the following:

http://foursquare.com/business/venues