Invoke & receive XML String Through URL

[tusharvichare]

I am developing a webservice here i ahve to give the url to the customer he will add the string to that url so that my service should update the database automatically.I had developed a small add method web service which takes two integers as input and gives added value of that this if i take in to my windows application it is working fine but how to test when the user invokes my url it should check for passed value here i am little bit confused which url i need to give to customer whether .asmx file are some thing else please give me idea how to procede.