There are multiple ways to get a vhost on IRC. You can request a BNC to use one of IRCNow's domains, or setup RDNS with NSD or Freedns, which will work on any IRC network.

Requesting one specifically for IRCNow's IRC

You can also request one specifically for IRCNow's IRC Network by messaging HostServ (see /msg HostServ HELP REQUEST) to request one and poke an oper in #help or #ircnow to verify it. Note that the vhost you request must either be a domain you own or a non-existent TLD.

For example: im.a.cat.meow is ok because .meow is not a TLD, however meow.im.a.cat is not permitted unless you own it, since .cat is a real TLD.