Additionally, the beta version features drag and drop message organization, a message preview pane, keyboard shortcuts, right-click menus and search capabilities for e-mail headers, bodies and attachments.

The updated version will allow users to open and read multiple messages simultaneously, as well as view all e-mail headers through a folder (rather than having to scroll and refresh, repeatedly).

Yahoo worked with Oddpost Inc., a company that provides Web-based e-mail applications to incorporate advanced technologies including DHTML, XML and SOAP, for improvements in efficiency and functionality, according to the news release.

"We constantly listen to feedback from our users with the goal of providing the best Web mail experience available," Mahon told Ziff Davis Internet News.

"Yahoo acquired Oddpost in July 2004, in part for its technological expertise in DHTML, which is incorporated into this beta.

To read about how Yahoo revamped its local search, click here.

The Oddpost team is now part of the Yahoo Mail team and they have been making enhancements to Yahoo Mail and across the Yahoo network since they joined."

Yahoo's new and improved Web Mail is compatible with Firefox (for both Mac and Windows users) and Internet Explorer (for Windows users only) and requires no software downloads, as it remains browser-based.

The service is available, as always, free of charge, receiving support from advertisers. It will continue to offer users virus and spam protection.

"This beta gives people a faster and more dynamic way to experience Yahoo Mail," said Mahon.

"We're excited to be testing some features that other Web mail providers don't offer," she added.

Yahoo is giving beta-version access to a limited number of users, beginning September 14.

Testers will be able to toggle between the new and existing versions of the e-mail service in the coming months, until the testing phase comes to a close.

For more information, or to sign up as a tester, visit the Yahoo Mail beta Web site.