This Webreference Newsletter has a good piece on some best practices for deploying a content management system.  The author makes a very good point about content conversion: While some of it can be automated there is always going to be a fair chunk of content that will have to be moved into the new system by hand. This is usually going to be due to the existing content not fitting perfectly into the new structure or that it was poorly deployed in the first place and now has to be redesigned.