Yahoo joined today the large plethora of companies that offers applications for iPhone through the AppStore. The web giant is targeting the users of social networks, who will be able to stay in touch with their friend through iPhone and OneConnect.

Unveiled earlier this year at Barcelona Mobile World Conference, OneConnect is a socially connected address book combining e-mail, SMS, instant messaging and social networking.

The service support sites such as Facebook, MySpace, LinkedIn, Hi5 and others and will be compatible with instant messaging services like Yahoo Messenger, Google Talk, AOL Instant Messenger and MSN Messenger. A feature of oneConnect, called Pulse, will allow a user to quickly see what is happening across various social networks.

OneConnect for the iPhone will be offered as a free application in the Apple App Store.

"The iPhone has ignited and captured the imagination of what a mobile phone can do," said Marco Boerries, executive vice president, Yahoo! Connected Life. "The rich feature set of the iPhone enables the best way to experience oneConnect. The powerful combination of Yahoo! Blueprint, the mobile platform, and the iPhone SDK, was leveraged to create this unique experience of oneConnect for millions of iPhone users."

The application was developed using Blueprint, a development environment Yahoo first introduced earlier this year to allow developers to build applications that can work across a range of phones.

Blueprint offers a standards-based language, easy-to-use toolkit, innovative features, and support across multiple runtime environments - allowing developers to maximize their reach across thousands of mobile devices.

Yahoo! is using Blueprint internally to develop iPhone applications and is in discussion with Apple on how to make Blueprint for the iPhone available to other developers.