Easy migration from other host?

I am moving all my sites from Webhostingbuzz to Dreamhost. Webhostingbuzz uses cPanel which has a built-in function for creating a full backup containing everything from the site content to mail content, ftp-content and database-content. It ends up in one large .tar.gz archive. Is there an easy way to unpack this archive in Dreamhost and have everything set up automatically or do I have to do everything manually?