Google’s interest in mobile phones market is not a novelty. In several occasion, Google’s officials expressed their interest in building new services and platforms for the mobile market. So the latest rumor brought to us by Wall Street Journal might have some grounds.

Quoting sources familiar with the matter, Wall Street Journal claims that Google is developing a new search platform for mobile content such as ringtones and downloads.

In fact, Google is working with content providers to index materials from entertainment and mobile-media companies in order to build a large gateway for users to find more rapidly their favorite ringtones, backgrounds, or game.

The users will be able to purchase the content directly from this platform and according to Wall Street Journal the Mountain View eventually plans to charge providers for higher placement in the search results.

Already Google has released some of its services, as Google Search and Gmail for mobile phones, and earlier this month some reports indicated that a mobile version of Google AdSense is in beta test.

Last year, in an interview with Reuters, Eric Schmidt, Google CEO, expressed his believe that mobile phones should be free for the consumers who will accept to watch targeted forms of advertising.

Also earlier this year there were rumors about a Google mobile phone, but the company declined to comment.

It remains to be seen if Wall Street Journal report will be just a rumor or indeed Google is “cooking” something new for mobile phones in its labs.