I have to disagree on the "steep" learning curve: the first steps setting up the server software were pretty straightforward...getting the first "wizard" website up and running was not difficult.. though it may be a good idea to collect the existing info in one place.

Then the installing of the "umbraco packages" using the developer / import package option is also very easy .... maybe a bit too easy because the over enthousiastic newbie will make a mess of his new website with a lot of datatypes, macro's, xlst files and whatnot and you in a few minutes have imported more stuff then you can keep track of. A more strict naming policy would help there.

I would be available for writing / reviewing part of documentation. Using a wiki seems to be the best way to do this. And to point all readers & prospective writers to the same wiki ?