Join the Local Search Authorities from Justin Sanger at ClickZ looks at something familiar to many who do local searches at major search engines -- how results from other local search engines like SuperPages, Citysearch and Switchboard always seem to be popping up. Lesson? If you can't beat them, join them. IE, if your local search company can't win for a local search term, be sure you are listed with those who are winning, these local search "authorities," as Justin calls them.
Of course, down the line I expect the major search engines to stop listing aggregators like this. Why would Yahoo Local point at a page at Citysearch that points to actual locally-oriented pages if Yahoo Local can do the same itself? Fortunately, that isn't an issue for the local merchant that's focused on doing well with the aggregators and the local search pages of the major search engines, as well.