Preservation strategies can be overwhelming, but these summaries don't sound so bad:

Migration - Transferring digital materials from one media or format to another due to obsolescence, software updates, etc.

Emulation - Copying a piece of software or hardware so that other processes think the original equipment is still available in its original form.

Encapsulation - Grouping together a digital object and anything else needed to provide access to that object.

Now, don't forget about the metadata!