How do you create a fake host name in IRC chats?

Everytime I enter an IRC chat, it shows all of my information, such as my internet provider, IP address, etc. However, sometimes I see people come in with fake hosts. How can I create a fake host name?

Some clients will let you hook into the request for this information and at least will mask provider.

I think BitchX will do this for you, though you might have to do some configuration.