How to implement updating over internet

Hi. I've got an application that's pretty much finished that saves entries to an XML-file. Now I'd like to add a function to the application so that users can get the latest XML-file by clicking "Update datafile" in the application. Also, I'd like to add a function for those that edit the datafile to be able to send the XML-file to me automatically as an email. In other words, I've got two different editions of the application. One for the editors that add new content, and one for the users that just use the client to browse the content. Any help would be appreciated.