information on "filter" property of CSS

Can somebody throw some light on the "filter" property of the CSS. I am working on a program that requires to use this property. I would like to get more detailed documentation on this property. Any help would be grateful. Awaiting reply.

http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/reference/properties/filter.asp

Thanks Kang, that link you sent me was very helpful.