We've found a number of Google Places advertisements appearing on searches for 'Brand + Product Category' and include a link to a competitive local retailer. The advertisements represent an entirely new AdWords unit that we hadn't seen before and seem to be designed specifically for Google Places. A handful of examples below:
A search for 'Zappos shoes' (and similar variants):
A search for 'Gap clothes':
A search for 'Bennigan's restaurants':
A search for 'Starbucks coffee':
We've only seen these advertisements from San Francisco, which would suggest that these are being run a purely trial basis at this point.
We've also only seen the ads at the top of the right rail. This suggests to me that they are exempt from the auction process.
I'd say these ad units remove any doubts that Google is taking Places very seriously.