Just one day after Google opened its maps service to outside developers, Yahoo has followed suit with a maps API of its own. But unlike Google's approach, which relies on JavaScript to embed maps into third party pages, Yahoo has built its offering using XML and requires developers to link to its Web site.

Specifically, Yahoo! Maps API employs geoRSS, which is an RSS 2.0 extension that adds support for location information. Yahoo has also stripped out the need for latitude and longitude coordinates to make implementation easier for developers by simply using an address.

"Developers can now create customized maps by overlaying a variety of content onto an existing Yahoo Map including weather reports, school district boundaries, open houses, garage sales, vacation photos, and more," a company spokesperson told BetaNews.

Like its Google counterpart, Yahoo! Maps API is free for any user. Because the maps actually load on Yahoo's site, however, the company can still generate revenue from advertising. Google has hinted it may include advertising directly on the maps themselves.

Yahoo has opted to leave the beta tag off its new Maps API, saying the service is "an official, stable tool with a dedicated engineering team that's committed to continued development and innovation." Developers should be able to get a customized map live within an hour, the company says.