Yahoo has announced the availability of an "all-new" Yahoo Calendar.

Due to begin rolling out in beta to users from now, it claims to offer an "intuitive, online social calendaring experience".

The new Calendar is built on the Yahoo-owned Zimbra platform using the iCalendar (iCal) and CalDAV3 standards.

Now inter-operable with other online calendar services including those from Mozilla, Apple, Microsoft, AOL and Google, so users can share their calendar data.

Other new features allow for alerts, colour-coding, drag and dropping of appointments, to-do lists and zooming in and out functions. In addition, images from the Flickr photo community can be included.

The Yahoo Calendar beta is currently being rolled out the United States, Brazil, India, Taiwan and the United Kingdom. Plans for global general availability will be announced later this year.