Released today, Plaxo 3.0 is the first online address book and calendar to synchronize between Microsoft, Google, Yahoo!, AOL, Mac OSX, Thunderbird, and mobile phones. In a few words the ideal tool to keep you addresses, contacts and calendar.

The new version of Plaxo is available for free in seven languages: English, French, German, Japanese, Portuguese, Simplified Chinese, and Spanish,

The new version promises to transform the synchronization in a simple task. Bridging between disparate tools and services with automated, multi-way synchronization – without cables, cradles, or complicated software set-up is now possible.

“After a year of hard work re-tooling our service, this is much more than just another product release; we’re really introducing an all-new Plaxo,” said Todd Masonis, Founder and VP of Products. “Plaxo 3.0 is the platform upon which we can build out our ‘sync and share’ vision, giving people access to all their data wherever they need it, and enabling ever richer ways to stay connected with the people who matter in their lives.”

The new online interface to Plaxo is a rich AJAX web application, with multiple components, presented in a seamlessly integrated, interactive environment.

Plaxo 3.0 offers also an innovative new calendar, built by the HipCal team with Upcoming View, Countdowns, Weather (via mashup with Weather Underground), Photos (via mashup with Flickr), and calendar sharing.

Founded in 2001, Plaxo is an online address book service founded by Napster co-founder Minh Nguyen and two engineering students, Todd Masonis and Cameron Ring. In 2006 Plaxo claimed to have surpassed 15 million users.

One month ago, Comcast teamed up with Plaxo for their new communication center called SmartZone.