I made a good start at doing this: but then I ran into a heap of problems...
Firstly, it turns out that nearly every interesting Voynich-related site I've looked at over the past six years has stopped working: Voynich dead links significantly outnumber the live links. Furthermore, many dead links (even recent ones such as ms408.com) don't appear to have made it into the Wayback Machine. And "deeplinking" (linking to sites inside a website) into the Wayback Machine is a no-no in the ODP.
Secondly, while the intention of the Open Directory Project is that it should provide a categorized directory of useful resources on a subject, Voynich Manuscript research only rarely works like that. For example, some ODP editors wouldn't even link to the Wikipedia page on their subject because it is a deeplink within another resource (i.e. within Wikipedia itself), as opposed to a user's subsite. So only a tiny handful of sites (such as Rene Zandbergen's exemplary pages on the subject, my Voynich News blog, etc) would satisfy a hardcore ODP editor's criteria for inclusion.
In other words, though I hoped that the ODP section might be the right place to bring some kind of order to the disjointed heap of fragments we call Voynich knowledge, many inside the ODP actively argue that that's not what it's for.
But if the ODP is the wrong answer, what is the right answer?
Having just spent a few days tracking down a long succession of dead links, I think there are two main types of webpage that should somehow be actively preserved: research pages (analyses of features, mainly of Voynichese) and theory/hypothesis pages ("my theory that I have, that is to say, which is mine, is mine").
And so I've just started up Voynich Research and Voynich Theories (as subsites on GC's Voynich Central website), each of which I plan to maintain as a single index page giving links to (and brief summaries of) all the research papers and webpages placed there. Though the ODP won't allow links to the Wayback Machine, I can put them in here: though my plan (longer term) is to contact the people involved asking for their permission to put an actual copy on the site, which would be a somewhat better answer.
OK, it's not a perfect answer... but it's a start.