Hi ya Lee :), it is certainly possible to move files between sites, take a look at this codeplex project (
http://www.codeplex.com/SPDActivities), there is a section called "Copy List Item Extended Activity" this will have some good examples of the code required. I think the hardest part will be the actioning it when a page is published, may need to mess with the event recivers a bit or a timerjob maybe.
Hope that helps mate
Andrew Carter
.Net & SharePoint Consultant
See my blog at: http://blog.apc-solutions.co.uk