Yahoo has launched a new version of its web-based email service. Yahoo Mail is free to use, and includes unlimited email storage.

A new interface allows users to have instant-message conversations with users of Yahoo Mail, Yahoo Messenger and Windows Live Messenger without using a separate program.

Using new toolbars, users can select whether they wish to communicate with their online contacts via email or instant messages. They can convert emails to instant messages if they see that the recipient is online, or convert instant messages to emails for the recipient to read later.

Yahoo claims the new version is faster and more responsive, and also includes a new search feature. This allows users to refine their email search results by searching for a specific sender, folder, date or attachment type.

The new email interface includes tabbed navigation, so several emails or instant message conversations can be opened at once, as well as an integrated calendar and RSS reader. Users can also personalise the interface by choosing between six colour themes.

Current users of Yahoo Mail can choose to upgrade to the new version, or continue to use the Classic interface if they prefer.