Moving and deploying content between Sharepoint farms can be a pain
Chris O'Brien wants to save us all some aggrevation and has produced the SharePoint Content Deployment Wizard which is available on Codeplex
SharePoint Content Deployment Wizard - Home.
(Note its still in Beta)
If you have more robust needs you could check out the Megalogix tools. I have used them with sucess in the past. They are not cheap however.