You can check for Federally Registered trademarks, but there is no easy way to check for common law trademarks. A good trademark search will run several hundred dollars and still not give you a guarantee that you won't get an infringement lawsuit.
The full link for the trademark search is here From my popular trademark article found here: How Do I Determine If Someone Is Already Using a Mark? You perform a trademark search. You can 1) hire a service to search for you, 2) search the U. S. trademark records manually at a Patent and Trademark Depository Library, or 3) search online using the form below. Searching for trademarks, though, is an imperfect science, and no search can be expected to discover all potential users of a mark. Remember that trademark rights are created by the use of a mark, and not by registration. Thus, unregistered marks may be valid marks--and they are much more difficult to discover. Registered marks, on the other hand, are easily searchable through the U. S. Trademark Office. Hiring a search service will usually yield the most thorough search, because such services search the federal trademark registries, state trademark registries, and "common law". Common law trademark searches often search sources such as phone book records and the like. Such services cannot guarantee that such a search will find all marks. Also, even if a mark shows up on a common law search, that does not mean that the user of that mark has any rights at all--you may need to do further research.
http://tess2.uspto.gov/bin/gate.exe?f=tess&state=sf7kbl.1.1 Thats from the United States Patent and Trademark Office.