Mike Blumenthal has been vigilant about uncovering and reporting abuse of Google Maps's Local business submissions. In fact, in the past week or so, he has reported a couple of cases of Google Local abuse, where companies submitted hundreds or even thousands of listings for their businesses even without having the required physical presence in that location.
Greg Sterling at Search Engine Land has a good summary of Mike's findings with Bulk Upload 'Mapspam' On Google.
Mike has been heard, and Jen from the Google Maps team responded to his concerns saying more tools are on their way.
It appears Google Maps is creating a spam fighting tool:
We're actually working on a solution right now that isn't just relying on the vigilance of folks such as yourself. To make the bulk upload / Local Business Center world better for everyone, I can't really tell you anything about what we're doing to keep these spammy listings from entering the Maps index.
That is all the information I have on this tool, I suspect we will learn more as we get closer to the release.
Jen adds that they currently do not have an easy form to use to report Google Maps spam. But the reason behind that is because "there haven't been enough reports to warrant one," she said. But if and when the reports increase in the forums, Jen promised to add an easier way to report Google Maps spam.
Forum discussion at Google Groups.