Update Nov.20: Click to call includes Canada and new link that explains Search History feature..
Google Maps Click-to-call:
Looking for a business on Google Maps in the US or Canada? If you'd like to talk to them on the telephone, simply click the "call" link and enter your phone number to be connected. Local and long distance charges are also covered. Here is an example search for hardware stores in Detroit. [Read news and blogosphere analysis on this feature]
Google Personalized Search now includes Google Maps - From the Google Blog posting: means you'll no longer have to remember searches you do for addresses, businesses, or directions on Maps. Instead, you'll be able to browse, search for, and bookmark them directly from your search history, just as you already can with your web, images, news, Froogle, and video history. Google has this page to provide you more information on the feature.