Institute of Real Estate Management ~ (http://www.irem.org/)
This site is complicated but has good resources.  Bypass membership features and go directly to Owners/Investors tab.  You will find good information and search for IREM members by state, name and member or property type they manage. 

LinkedIn ~ (http://www.linkedin.com)
LinkedIn is like Facebook for professionals and businesses. Find property managers and businesses and see their resumes and professional recommendations. And you will be able to browse LinkedIn’s Q&A sections with tips about filing taxes to property repairs.

Yelp ~ (http://www.yelp.com)
An interesting tool to use about businesses and individuals of almost all kinds.  This site has service reviews by customers.