This is all a little bit strange. I've been having the same problems - not able to connect to any sites except this one. Looks like it was right across the network and not just a local issue. It does seem to have been resolved except there's one site I still can't connect to:
http://vancouver.cs.washington.edu/. Not a site that many would visit until you realise it is a web integrity checker - you visit the site and it lets you know if your browsing is being intercepted. The site was discovered during the Phorm discussion. Can anyone else connect to it please? Especially VM customers?