Our telnet address is cryosphere.org (or cryosphere.net, or 188.8.131.52) port 6666. You might be able to connect by visiting telnet://cryosphere.net:6666/, although this is likely to run a rather inadequate telnet client.
You can also connect to us securely with telnet over SSL.
For Linux, we suggest using our own client, crystal.
There are, of course, many other clients available for all platforms. Some of these we've reviewed for compliance to the specs. Sadly, the results are generally appalling.
If all else fails, you can connect with the java client on this website.