http://wiki.debian.org/ReleaseGoals/FullIPv6Support (there is also a link on that page to a listing of bugs that are already tagged IPv6)
- Haven't checked yet but wouldn't be surprised if all of the FTN related applications in Debian that have network capability, like binkd or ifcico (part of ifmail) for instance, do not have IPv6 capability as yet.
- Citadel does not yet have IPv6 capability?
- INN ?
- UUCP is already listed but notes are about usage via ssh or etc.