When we spend a day hitting yard sales, it's usually a haphazard system. Grab the local paper and circle the sales, make a list, and figure out the best route. Often we just hit the first few and then wander around looking for signs of more sales. We love serendipity.
But a listener suggested we try the Yard Sale Treasure Map. It's a free app for iPhone/Android that lets you enter in info and it makes the best route for you. The mobile app even hooks into Craigslist to suggest sales in your area. Cool!