Microsoft made available as of July 5 the completed version of its Silverlight technology for Symbian via Nokia's Ovi store.
Microsoft and Nokia announced plans for the Silverlight for Symbian release in 2008. At that time, the pair said to expect the final code before the end of 2008. In March 2010, Microsoft released a beta of the Symbian Silverlight technology.
The new release is for the S60 5th edition phones, including the Nokia 5800 XpressMusic, Nokia N97 and Nokia N97 Mini, according to the Nokia Web site. According to a blog post from the Silverlight for Symbian team, there are more than 20 million users of those model Nokia phones worldwide.
The newest Silverlight port will allow users to view Silverlight applications in their mobile browser, as well as to make use of related tools to build Silverlight applications that target the Nokia phones.
I've asked Microsoft whether there's any update as to when (and if) the company might release a version of Silverlight for the iPhone or Android phones. No word back so far. Microsoft officials have said Silverlight is one of the development platforms for the forthcoming Windows Phone 7 devices, but that Silverlight won't run in the browser on the first Windows Phone 7 phones when they are launched this fall.
(Thanks to @robertmclaws for the original heads-up on the Symbian for Silverlight release and to @manan for the download link.)