Check if WSE 3.0 is already installed

Question

I am ready to distribute a small utility to a large number of customers.
This utility requires WSE 3.0 (Web Service Enhancements) installed on the client machine because it needs to connect to a web service on which I don't have any control.
In the setup package I have included the redistributable MSI from Microsoft.
Now, I wish to execute the install action only if on the client machine the WSE isn't already installed.
How to check this? Any registry key, componentID or whatelse?

Answer 1

check if a registry key exists before installing

http://keystrokeesbnet.codeplex.com/discussions/228604