Keyhole is a supplier of online satellite maps that allow users to zoom down to street level to specific locations. Keyhole’s system is built on a multi-terabyte database with trillions of bits of mapping data collected from satellites and airplanes.

Google also revealed that it had cut the price of Keyhole’s mapping service to $29.95 a year from $69.95, effective immediately.

With an Internet connection, a user can enter an address or other location information and Keyhole’s software hooks up to a database and takes the user to a digital image of that location on computer screen.

The three-dimensional, interactive software gives users the option to zoom in from space-level to street-level, tilt and rotate the view, or search for other information such as hotels, parks, automated-teller machines, or rail connections.

The purchase allows Google to match rivals such as Yahoo and Microsoft’s MSN, which offer online mapping services of their own using detailed drawings that allows users to zoom down to street-level scale.

There has been some speculation that Google is increasingly willing to expand beyond its core search engine capacity. In mid-October it unveiled its desktop search software, giving it a first-mover advantage over rivals Microsoft, AOL, Yahoo, and Ask Jeeves, which have all identified the area as the next search battleground.

Google Desktop is a free download that, when installed, indexes local documents such as emails, office documents and instant messenger conversations and then allows users to search them via their browser.

There has also been some speculation that Google is quietly building a web browser to compete with Internet Explorer (it owns the domain gbrowser.com), and an instant messaging client, although it denies this.

Google recently reported its first set of quarterly financial results since going public in August. For the three months to September 30 the firm reported net income up 154% at $52 million on revenue up 105% at $805.9 million. Excluding a $201 million charge to settle litigation with Yahoo, related tax benefits, and other charges, the net income would have been $125 million.

Almost all of Google’s revenue comes from advertising placed on Google’s web sites and sites owned by partners.