newby's Web service problems, please help!!!

Question

Hi everyone, I am a newby but very interested in .NET and webservice, and I do want to learn something from your help. I am developing a small webservice using c# and it is really convenient. But I have some problems. I want to let the webservice to extract related information based on certain content of a HTML webpage, like get the date-of-birth and name of a person based on the person's ID(all these info are displayed on the HTML page) and display notifications if necessary. How can I make my webservice capable to read the HTML web page? And I tried to use MessageBox to display the notification but the webservice told me I should specify a ServiceNotification or DefaultDesktopOnly style, but I have no idea about them. Please tell me what to do. Thank you in advance