First of all let me thank to M. Orçun Topdağı for pointing out a useful cs file in the samples provided by Microsoft.You may get those samples in the below location.
[Install drive]:\Program Files\Microsoft Visual Studio 9.0\Samples
The file is Dynamic.cs which provides a bunch of functionality to work more with Lambda expressions.That sample was written for .Net 3.5 and I was afraid whether I can use that in my Application since I am working in Silverlight 3. But I was able to use the same classes for Silverlight and a sample which takes Lambda Expression from xaml and executes through converter is attached with this post.
How to specify a Lambda expression in XAML data-bindingI am using the ConverterParameter to get the lambda expression.The no of parameters to Lambda expression is limited because we can pass only one value to the converter. In the above sample I have set DateTime.Today as DataContext of the UserControl in the constructor.So it will take that value into the converter.Here is the converter code.
Now you might wonder where is the System.Linq.Dynamic ? Here comes the importance of Dynamic.cs which I had mentioned at the beginning.You may find all those classes there.
Download and enjoy the sample here.