Ajaxterm is a web based terminal. It was totally inspired and works almost exactly like Anyterm except it's much more easy to install.
It is easy to install (download, untar, run!) and its terminal support looks pretty good to me. Unlike Anyterm, nothing to compile, no external library to install (except Python), no Apache to mess up with (none of my servers are running Apache) and it is far easier to deploy. To hide behind a "proper" HTTP server, just proxy it with appropriate authentication.
It can provide you a shell over HTTP/HTTPS, bypassing draconian firewall rules (like most corporate firewalls). The terminal emulation is actually quite good, and I have no issue running many terminal apps that I frequently used (w3m, vim, mutt, etc).