I updated the Wiki a few weeks ago when I heard, but don’t think I posted anything here. Comcast has changed their delisting form page to http://postmaster.comcast.net/block-removal-request.html. The old form is currently non-functional. You can fill it in, but it’s unconnected to anything on the back end and it won’t result in an IP being delisted from the various Comcast blocklists.
My understanding is that the old form may come back to life at some point, but it’s much safer to use the new form and the new Comcast Postmaster Site.