Is There An Association Of Marketing Communications Firms Where Information And Location Is Listed?

I'm not sure if there is an actual association that has a list of all marketing communications firms, but I do know of a site that has  a lot of good general information about services that marketing companies provide.  They have explanations about Search Engine Optimization, Social Media, Link building, reputation management and pay per click (which I think is awesome if you're an advertiser because you can customize where your ads show up based on keywords and location, for example if I did a Utah Pay Per Click campaign, google ads would show up on computers of people living and searching the internet from Utah or for people who are searching for Utah terms relating to what I'm selling.) The internet is incredible these days and can do so many amazing things.  Check out Vizad's website and it will give you a good idea of what marketing communications firms are offering these days.