Here's a sample:

This does NOT affect your map ranking or search engine ranking.
If you use it and you get rotated into the first page of the map for areas, it will definitely help out your business by attracting people to your map listing. Right now few people are using it as it just came out. Eventually more and more people will start to use it and it will lose it's affect, but the price is still low enough that 1 job a year pays for it.
First you need to make sure you have added your Google Places listing, or claimed your listing.
Whether you need to claim your listing, or get started on this new advertising method go to http://www.google.com/local/add/businessCenter and login.
Scroll down the page and you'll find an option for "Make your listing stand out on Google"
Select the option for Highlight Your Website
Click Proceed to Billing, Fill out your billing info and start working on your tag! Watch the results carefully. I'd recommend going with each ad for 2 weeks and see how they do. Rotate through a few to find the ones that give you the best results.
When you're done or if you have questions, go to http://www.homeinspectorpro.com/inspector-forum/Search-Engine-Optimization/2563-SEO-TIP-Google-Map-Advertising-Tag/ to the message board thread on this topic. Let us know how it's working for you! I want to hear results!!
Oh, and I guarantee that you guys will start getting calls from companies 'offering' this service to you for $50, $100 or even more per month. Hang up on them!
Now you know, and knowing is half the battle (hmm, sounds familiar).