Choosing the right categories in Google is not so easy as Google does not tell you what they are exactly.
You might find something close but how do you pick other categories? Consensus out there at the moment is you should not make categories up, but use what Google has available.
Mike Blumenthal has released a tool which shows US database of Google Maps Categories.
It can be found here
See also this nice article about Google taking over its own serps on Techcrunch;
Google, These Aren’t Really The Best Answers For Users. They Are The Best Answers For You.
