More and more networks are offering virtual host addresses (aka vhosts). You usually have to have a registered nick with the network, and then have to request a vhost either in the help channel (usually #help) or a specific vhost channel.
Details on the availability and method of obtaining a vhost is usually available in the general help channel.
Thanks a lot, it seems to work as I wanted. Now, how do I change my full name? The menu in the options wouldn't let me.