The premise is much like the graphics shops some people have been running at Hogsmeade, but with a few differences. For one, these shops will be open all the time. But the best part is that shopowners will earn their house POINTS for filling graphics orders.
Membership is moderated and you will be approved to join as long as you are a member of HIH and have been sorted to a house. Posting access will only be approved for those of you running a shop and there is an application for you to fill out to sign up for that.
So head on over, check out the info, and JOIN. :)
ETA: and also, hogsmeadewkends now has a new layout.