Once your database is up on the new machine in 8.0.4, you would then migrate it using any of the standard migration methods. You would copy all files relevent to the operation of the database; data files, control files, redo log files, archived redo logs, password file, init.ora file, etc. This copy would happen when the database had been shutdown in either normal or immediate mode. You can manually swith the logfile if you want, but it is not necessary since the database will be down when you copy it.