We have an ex employee who resigned from the company who is using our company name on his competing business site for search engine purposes. He started "innocently" enough by releasing a web based press release stating that he had resigned from our company to start his company. He is now aggressively using our company name in the following format:
His Company Name and Our Company Name
on his website and blog entries. He is not using the name in the metatags, just the content of the site. His site now appears in position 3+4 (ours is 1&2) when searching Google, MSN and Yahoo for our company name. There in not a non compete agreement in place. Although I don't care that he is a competing business, we spend a lot of money advertising our company name, and it seems wrong that he can poach off of our name in the search engines. Are there any legal actions that can be used here?

Get a lawyer and sue his a**

I'm not a lawyer either, but from your description, it seems like shakey ground for him. If he wants to spring off on his own, great, that's free enterprise, but using your name to do it, I'd say that's a problem. Using your name without permission is an extreme risk on his part. It should be stopped.