In addition to its own Silverlight multimedia technology, Microsoft will support Adobe's competing Flash technology on Windows Mobile phones, the companies planned to announce on Monday.

Microsoft has licensed Adobe Flash Lite, the Flash Player runtime for mobile devices, so that Windows Mobile phone users can view Flash content in the Internet Explorer Mobile browser. Microsoft has also licensed the Adobe Reader LE software, so that Windows Mobile users will be able to view PDF documents.

The announcement means Windows Mobile phones will support both Flash and Silverlight, Microsoft's own fledgling technology that lets developers build multimedia Internet applications that run in browsers.

Microsoft hasn't yet said when it will add the support for Silverlight to Windows Mobile, and nor is it saying when it plans to support the Adobe programs, said Scott Rockfeld, group product manager at Microsoft's Windows Mobile group.

The companies have some integration work ahead of them. "The engineers have to work together to integrate the technology, and then the platforms have to be distributed to OEMs," said Anup Murarka, director of technical marketing for mobile and devices at Adobe. Adobe hopes that the capabilities will be found in phones by the end of the year, "but that's something Microsoft would have to comment on," he said.

Having both Silverlight and Adobe Flash on Windows Mobile is a natural, Rockfeld said. "From a Windows Mobile perspective it comes down to choice," he said. "Flash and Silverlight can provide similar experiences, just like we see in other areas." For example, Microsoft's Live Search and Google Maps, which offer similar services, are both accessible from Windows Mobile phones, he said.

Regardless of which technology users are most drawn to -- Silverlight or Flash -- the technologies both enable the types of multimedia content that phone users are interested in, said Julie Ask, an analyst with Jupiter Research. Her research shows that consumers who have phones that support rich browsing experiences, like the iPhone and some Nokia phones, generate more page views and are more likely to sign up for a data plan with their operator, she said.

"Adding Flash into the user experience on the phone will make it a better one, a richer media experience," Ask said.

Microsoft said last year that it would develop Silverlight for Windows Mobile. Earlier this month, Microsoft announced that Nokia will use Silverlight. Nokia said it planned to ship phones running its Series 60 software that support Silverlight by the end of the year, with Series 40 and its Internet Tablet to follow.

Nokia, Samsung, Motorola, Sony Ericsson and LG are all shipping Flash-enabled devices today, Murarka said. In addition to supporting Flash-based content on Web sites, mobile-phone makers and operators can also use Flash in content like screen savers, wallpapers and animated ring tones. Flash is also used in mobile-phone user interfaces.

Notably absent from the list of handsets using either technology is the iPhone. "We'd love to see Flash come to the iPhone," said Murarka. But just like any other phone maker, Apple would have to work with Adobe to license Flash for the iPhone. "Hopefully when we have the opportunity to review the SDK, and if it's a vehicle to deliver a solution, we would look forward to working with Apple," he said. Apple recently released an SDK that will allow third parties to build applications for the iPhone.