It looks like the Windows Live Mesh Client for Macs is available to download again, but I don’t think it is quite working yet. Intriguingly after I downloaded and tried to install the Live Mesh Client it told me the newly downloaded file was older than the one that was already on my Mac, which I had downloaded when it became prematurely available a week or so ago. On running the previous version or the new version I get a request to update or cancel.
According to the download page there is great demand for this, and they are pushing the app out the door before they had planned to, so hopefully this will be up and running soon.
With all of that in mind, here’s the link to the download page.