Microsoft has launched a bid to capture a segment of the growing market for rich web content on mobile phones.
Microsoft's Silverlight has been called a "Flash Killer"
The software firm has signed a deal with handset manufacturer Nokia to bring its Silverlight platform to millions of mobile phones.
Silverlight is seen as a competitor to Adobe's Flash, which is already used by popular websites such as YouTube.
The software will first be available on Nokia's high end smart phones running a Symbian operating system.
Nokia's S60 platform, which uses Symbian, will be the first to take advantage of Silverlight.
S60 is used in handsets built by LG and Samsung as well as Nokia and is the most popular smart phone software platform with more than 53% market share.
It is used in Nokia's latest N96 phone, the successor to its popular N95.
Other handsets and internet tablets running different software will follow at a later date, according to the firm.
Silverlight allows designers and developers to produce rich web applications that are independent of browser, operating system and handset.
Microsoft has stressed its value for developing Web 2.0 applications that would work on a computer, but also on any other device including mobile phones.
The software enters a marketplace already dominated by Adobe's Flash, and its recently launched Air product.
Flash is already on millions of mobile phones.
Adobe has agreements with 18 of the top 20 device manufacturers worldwide including Nokia.
And, according to Adobe, 450 million devices have been shipped with the cut-down version of Flash, known as Flash Lite.
Microsoft will hope to compete with this presence.
The firm is currently working on a version of Silverlight for its own Windows Mobile software.