Fortunately, some kind soul has had the same problem and produced a script called debtakeover to migrate a running server to Debian. So I'm about to try it out, having backed up everything critical. 1&1 do give you a facility to boot an emergency system off a network drive if you screw up your config, so I should be able to put everything back the way it was if I screw it up too badly. But wish me luck...
www.plokta.com will be down for a while, and I won't be able to receive any email.
