Yes it is possible to migrate the content from one ECM product to another. The amount and complexity of the content will affect the method which is best suited to the method you choose
I work for Vamosa, a company that specalises in this area. There are a number of whitepapers etc on content migration available via www.vamosa.com or please feel to contact us for a chat / advice on how best to go about the migration. The number is +44 (0) 574 2500.