To be able to do a disaster recovery, you need exactly the same versions
in source and destination. For the database restore/attach Todd sent,
you need the destination to be the same product (e.g. MOSS2007, WSS3,
SPS2003, WSS2, etc) and for the destination to be the same or newer. If
the versions aren't the same you will be forced to attach using stsadm
which will automatically upgrade the database to match the destination
version.