I want to echo some of the sentiments of:
http://www.haskell.org/pipermail/arch-haskell/2012-August/002126.html
(I joined the list after reading that message.)
I'm starting out doing Haskell development and am a long-time Arch user, and hence I am keen on keeping Arch Haskell up and running and working towards the all-of-Hackage goal.
I think documenting process is a great idea, and I suggest you just go ahead and start pete, e.g. working on the wiki.
Keep the mailing list informed, hang out in the IRC channel.
I'll help out when and where I can as well.
Cheers,
Ramana