minimal checklist of services to consider when doing a migration 

* user + groups
* apache (SSL cert is in /etc/ssl/server.pem)
* roundup instances (both 0.7 based and 0.8 based)
* mailman
* home-directories: check current usages
* DNS/BIND: check that we can easily switch within a few hours
  none of the code* servers is dns server for codespeak.net or pypy.org,
* subversion (1.3 fsfs based repo + hooks) 1.2.3 is installed, we can
  wait for 1.3 being officially released by gentoo as we do not need any
  of the new features.
* vadm/versioning of system config files
* postfix: main/master.cf migrated, soft_bounce on
* hotsync for repository 
* backups
* awstats/statistics configuration