Yes, a migration script exists (link is in implementation guide). It's pretty good. It gets your basic incident information, contacts, permissions. If you want/need additional stuff it shouldn't be too hard to have it migrate additional data as well. If I recall, I wanted something to snag the 'request channel' as well and it was easy enough to do if you know your SQL and db schema. It will only migrate closed (100%) incidents, so if you consider all the migrated stuff to be historical anyway, you'll likely be happy with the results.