EarthLink will roll out a beta of a new members-only Flash-based Web e-mail within four weeks, the Atlanta-based Internet service provider said Thursday, in a bid to upstage rivals such as America Online and even Google.

Unlike other Web-based e-mail systems, such as America Online's new subscriber-only service, EarthLink's upcoming Enhanced Webmail is built using the Laszlo platform, which generates Flash-based applications. Most existing online mail services, including those hosted by AOL, Google, and Microsoft, are built on DHTML (Dynamic HTML).

"We've been the first to market [among national ISPs] in a number of areas, like anti-spam technology," said Jerry Grasso, EarthLink's director of corporate communications. "And this plays right into that. Flash lets us build a rich new application, the first in the business that duplicates the desktop e-mail client experience on the Web."

By using Laszlo and generating a Flash-based application, EarthLink figures to sidestep the basic problem most users have with Web mail: it's slow and clunky.

"We've taken a completely different approach than, say, AOL and Google," said John Foltz, the product manager for EarthLink's e-mail. "It doesn't behave like a Web page at all."

Among the features possible with something like Flash, he went on, are keyboard shortcuts identical to those used in desktop mail clients such as Outlook -- the Delete key erases messages, a Shift-Click maneuver selects multiple messages -- a single page interface, and in-the-background mail transmission.

Foltz hammered on the single page interface idea. "There's never a page refresh, so it works exactly like a desktop application," he said. "Web e-mail is certainly more convenient [than POP3-based mail], but people don't use Web mail more because it's so slow. We're addressing that."

When clicking on a message header, for instance, to see its content, a user of Enhanced Webmail sees the message body in a preview pane almost immediately, and without the browser redrawing the page. The most current messages, in fact, are pre-cached when the user heads to the site, so that message content appears instantly.

"It behaves very much like Outlook," Foltz said, comparing it to the popular Microsoft e-mail application.

The interface is also significantly more customizable than the new version of Web e-mail just rolled out by AOL, promised Foltz, who demonstrated how users will be able to resize panes and reposition elements in the browser window.

Out the gate, Enhanced Webmail will offer 100MB of storage for each mailbox (each EarthLink account can have as many as eight mailboxes), but the ISP plans to boost that to 1GB -- matching Google's free Gmail -- by the third quarter.

While Foltz said that a beta of Enhanced Webmail would be available to EarthLink subscribers in about four weeks, the final release is on the calendar for May.

Like AOL, EarthLink plans to offer the Flash-based mail service first to its subscribers. Later, it may open Enhanced Webmail to non-members. "Our tentative plans are to have a broader e-mail product later this year," said Grasso. "At this point, though, we're only evaluating that." He wouldn't promise that EarthLink would move into the for-free Web-based mail market.

EarthLink didn't hesitate to hype rich Internet applications, such as its Flash-built online mail, as the wave of the Web's future. "Rich Internet applications are a bit like what the Apple Macintosh did to the user interface when everyone else was running DOS at the command line," said Grasso. "They're going to change how people work on the Web."