Formerly known as Google Boost (introduced October 2010), the service - which enables advertisers to set up ad campaigns quickly) has expanded and is now available to all U.S. businesses - it was previously limited to small test group of advertisers.
Advertisers interested in AdWords Express will likely be those seeking new customers to their website or Places page but which don't have much in the way of performance-based advertising experience. Businesses will provide some basic category information, create their ad and set a maximum monthly budget. Google will then recommend a budget to Adwords Express businesses based on ad competition.
While it is difficult to determine if there is a general need for Adwords Express, it's obvious simplicity coupled with Google ability to whet the marketing appetite of the Web community will reserve the service a formal spot at the table.