If the server resolves your hostname there is nothing you can do about it I'm afraid. Even if it did just show your IP, someone could use the /dns command to resolve it and find your hostname anyway.
TBH, it's not that revealing...if I was told to find "Nicon" in Cambridge (which is the only information I can see) I wouldn't know where to start. Plus, I only know what "cmbg" is because I live near there...some weirdo from, say, Australia, would not have a clue and probably not know that NTL is uniquely a UK ISP (I believe). With the right equipment, your IP would be used much more to trace you than your hostname would anyway.
It is possible to connect to IRC through a bouncer (BNC) which can provide you with a vhost (virtual host) - Those are the hostnames you often see with "i.am.an.elite.sessy.donkey" or something. These do cost money.
Search the board for "BNC" and you'll find a number of threads with information about it. Expand to 'All Posts' and 'All Forums' for best results. You could also search
Google, or ask in a #BNC or #ShellHelp channel.
Some networks also have a mode which can be set on your nickname that will cover your host up with a set vhost. Two prime examples of this is Undernet and Quakenet. When you register an account with them you can set your vhost by setting mode +x on yourself (on most networks it is +x or +X). Ask in the network's #Help channel for more information, or check out the network's website. Once again you can use Google if you don't know the website address.
Hope this helps
Regards,
