Joining the herd of Web sites jostling to cash in on the holiday shopping season, online search engine leader Google Inc. is adding a tool designed to make it easier for consumers to map out their local trips to the mall.

The feature, unveiled Tuesday at Google’s Froogle shopping site, pinpoints merchants selling a specific item within a designated ZIP code. Besides displaying a map showing all the local stores carrying the merchandise, Froogle also lists price differences.

Initially, Google is depending on a contractor to pull the inventory information from several hundred major merchants. The search engine hopes to make the service even more comprehensive by encouraging stores to submit their own customized merchandise list to the newly created “Google Base” — an information clearinghouse for everything from family recipes to scientific formulas.

Earlier articles about Google Base expressed a fear of this happening. I guess they were right.