Any solution to trap all my requests without calling my web service

I am writing an application that does statistical analysis on Requests received by Web Applications. I am providing a web service interface that should be called by Web Applications in order to log the HTTP requests they get. I do NOT want my potential client to write the code to trap all his requests and call my web service. I want to write a pluggable component and give it to my clients so they can get this functionality by configuration. Please suggest a ASP.NET Solution to solve my problem