Those three sites come up VERY high as organic search on your name/business.
Remember: What does the web say about you? Ask for those recommendations for Linked In..encourage people to do a recommendation for you on Yelp. Google Places let’s you put WHY YOU ARE UNIQUE..and all three encourage you to cross link. Put your other profile links on all three, plus your website, Twitter handle, whatever you have to show a potential client that you understand internet marketing and social media.
For free..why not?