Let me share my findings before asking the question.
Google Places API documentation says: \"Note: To use the Google Places API you must first request a Maps API cli
We opened up the Google Places API to all developers this week at Google I/O and simplified the Terms and authentication:
http://googlegeodevelopers.blogspot.com/2011/05/places-everybody-show-is-about-to-begin.html
You no longer need to sign your requests, but instead just use a key obtained using the Google APIs console. An AdSense ID is no longer required, but you will need to go though a credit card based identity check in order to upgrade from 1,000 to 100,000 request per day.
You can use the Places API in mobile apps that are free or sold online through a mobile app store such as the Apple App Store or Android Market. For fee desktop apps however will require a Maps API Premier license which will be offered once the Places API graduates from Google Code Labs.
For information on getting started, see the docs:
http://code.google.com/apis/maps/documentation/places/
HTH,
Thor