I wouldn't worry about linking to a site that also lists your competitors. People are likely to search around looking for service reviews and multiple vendors.

One option is to use the Yelp API to pull recent reviews into your site. I believe the API lets you pull in 3 reviews to display directly on your site:

http://www.yelp.com/developers/documentation/search_api

One thing to keep in mind when linking to Yelp is to avoid soliciting positive reviews. They want reviews to be as organic as possible:

http://officialblog.yelp.com/2010/08/dont-ask-for-reviews.html