Google publishes New Business Listing Quality Guidelines

Summary of major points:

• Represent your business exactly as it appears in real life. The name on Google Maps should match the business name, as should the address, phone number and website.
• List information that provides as direct a path to the business as you can. Given the choice, you may want to list individual location phone numbers over a central phone line, official website pages rather than a directory page, and as exact of an address as you can.
• Only include listings for businesses that you represent.
• Don’t participate in any behavior with the intention or result of listing your business more times than it exists. Service area businesses, for example, should not create a listing for every town they service. Likewise, law firms or doctors should not create multiple listings to cover all of their specialties.
• Use the description and custom attribute fields to include additional information about your listing. This type of content should never appear in your business’s title or address fields

Of course if you believe somebody is abusing the system… you can report it at Google Groups