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.

Comments:
Brett Gilbertson
02/14/2008 01:09 am
Interestingly, seven months down the track there is still no such tool. It's a bit of a shame, because the spam is on the increase, and the Google Maps forums are practically useless too...
bill
04/22/2008 12:56 am
I posted a question on Google Groups with my question regarding how to report spam on Google Maps. My post was not answered by anyone but now shows up in Google search results: http://groups.google.ms/group/Google-Maps-How-Do-I/browse_thread/thread/5740ed018f6a8a4f/50862d2d616dfa96 How can Google tell if anyone wants to report Google Maps spam if there is no way to contact them about it?
Jon
07/18/2008 01:35 pm
www.takelessons.com is spamming Google Maps Local Business big-time. They are located in San Diego and they are listing all of their independent contractor music teachers on Google maps in each city, without the teacher's knowledge or consent. All of their Google listings are the same, providing the same toll-free number. This must be really annoying to local businesses that actually have a real physical presence. I consider this practice to be highly unethical and it detracts from the value of Google Search.
Steve
09/25/2008 03:39 am
This idiot is using a Word Press Blog, hosted on his site so Word Press can't stop him http://www.peerlesspressurewashing.com/roofcleaningtampa/ This is classic Google Maps Spam.
Steve
08/06/2010 03:54 pm
This is the new wave in Google Maps Spam. Google Maps Forum spam with thousands of keywords repeated over and over again with the link in the sigs. http://www.roof-cleaning-institute.activeboard.com