Migrating your BitlBee instance to a different machine
If you want to move your BitlBee instance to a new machine, you can. You can usually find your account file(s) in /var/lib/bitlbee. Just copy them all to the new machine, and you're done. Make sure you set the ownership and permissions correctly on the destination machine.
If you get an error message when trying to log in on the new machine ("The nick is (probably) not registered") the problem is most likely related to bad permissions. Double-check that your bitlbee process is running as the user that owns /var/lib/bitlbee, and that all files in that directory are also owned by that user.
Since these files contain the passwords of the IM accounts of all users of the BitlBee instance, it is strongly recommended that the permissions on the directory are not too permissive. Never make it world-readable or even world-writable.
For users of public servers
These instructions work for people who run their own BitlBee server. If you're on a public server and want to use a different one without recreating all your accounts, this can not yet be done automatically. You can ask for help in #bitlbee on irc.oftc.net, at least if you're on one of the main public servers.