sending xml file to client

Question

What is the best way to send an xml file from an html web sever to a client without the client first having asked for it. I'm using ASP.NET for the main web page on my server. The client can of course ask for data from the server. I want to send a list of valid users as an xml file to the client after the users been enterd at the server and stored in an xml file. The file would then be transfered to the client for storage on the client. Thanks, Keith Stallings