Al the name adressed on the internet have a numeric ip.
To find the numeric ip use comand /dns name adress
For ex:
Dns resolved www.yahoo.com to 216.109.118.65

The reverse DNS is
Dns resolved 216.109.118.65 to p2.www.dcn.yahoo.com

so .. if u connect to IRC from the computer that has the 216.109.118.65 ip , when someone whois u , he will se something like this
YourNick is Ident@p2.www.dcn.yahoo.com

and not
YourNick is Ident@www.yahoo.com

That is because the reverse DNS is not resolved to www.yahoo.com even if www.yahoo.com is rezolved to the same IP.
So , the easy way to have a Vhost is to buy a shell !
The hard one is to buy a domain , and u need to speak with your ISP or the NS (name sever) administrator (witch is in the most of the cases the ISP) to resolve your ip to your domain !


Just Be Original !