We often have Clients inquire regarding what actions to take when a competitor "steals" their brand name or trademarked products/services. 

I came across an article (http://searchengineland.com/070903-150021.php) that summarizes several important cases of recent past.  These would provide an excellent point of reference allowing for research in greater detail on a number of issues relevant to Companies today trying to protect their hard won Brand Reputation.

There is a great deal more than initially incorporated in determining the rights of a trademark holder and as with most aspects of the law-there are still many shades of grey that have yet to be clarified.  This is an area of the Search Engine Marketing and Pay-per-Click industry that will be unfolding for years to come and represents the interests of many companies that have either already incorporated Search Engine Marketing into their Integrated Marketing Mix and those who have yet to put their toe in the water for a try. 

Regardless of what stage a Company is in promoting their interest in the Online Arena-their is relevance of what is going on today.  Have a look and see any of these cases would apply to your situation.