Silverlight if technology from microsoft and the development is done in Microsoft Visual studio. The Out put file can be viewed using silverlight player.

Flash is from ADOBE and development is done using Flash or Flash builder. The out put file can be played in flash Player which is much more popular than silverlight.

Both these technologies can be used to produce animations and rich interfaces. But more advanced applications can be build using Flash.

Hi Brad,
Which you write I know alreday.I want to know by development point of view.
Flash is mostly used for designing.What @ silverlight?
Thanks.

silverlight was initially focused on streaming media than applications and animations. Now its more focused on development of Rich Internet Applications which can be developed by existing .net developers without learning a new language. You can do animation and designing also but its not as good as flash is so its not globally accepted as a designing tool. Flash has come a long way in designing and animation in many years and is very friendly for designers and flex builder is friendly for developers. Microsoft Expression Blend is used for designing with silverlight.

Hi Brad,
Thanks For the reply.It clears.