lammert - 10:35 am on May 9, 2011 (gmt 0)
Hi deathlock, first of all welcome to WebmasterWorld!
Do you still want to display www.anodomain.com in the address bar of your browser, or is it OK to show subdomain.example.com there. If you don't mind which domain is shown in the address bar, a 301 redirect from one domain to the other is enough. Otherwise you have to put the second site in a frame, or use proxying between the two servers where the main server is requesting the other server for the pages, and then forwards those pages to the user.