I am in the process of reviewing various PPO's across the country. Is there any clearinghouse or informational material where I can get info on these around the country?

You can contact a benefits broker who will not charge you any fee, but will collect a commission from whichever carrier they place your company's business with. They usually have access to trends among insurers, reputations of carriers for price, quality (customer service)and network availability for your population, and knowledge of what is competitive for a group of your size, location and average age. I used to work for a benefits broker shopping plans for employers. A broker, if knowledgeable, can provide a very valuable service to an employer.