User Log should be Maintained in Web Application

Question

Dear Friends,
I have a Requirement in which the user who logs into the Web Application,when Users makes new Entries(Insert)  or any Changes(Updates) by Given Web form in the Web Application and where ever he(User) goes in web application like(Clicking on other Menu Link,Updating,Inserting,Cliking on Checkbox in web form..in short perform any activity in web application a User Log should be maintained of that Looged in user....that will show at this time User loggedin and done the activities in web application.
how can i maintain such a user Log by Web application in Database, my backend is SQL Server 2008.

Pls Reply!!!

Thanks,
Aamir