On some networks (more and more of them lately) you have to receive an e-mail from the network that you're registering on, which will contain a confirmation code. Until you send that confirmation code to nickserv, your nick may not show as registered, but as someting like confirmation-pending.
If you haven't received the confirmation code within 24 hours of sending the registration information, make sure that you check any spam or junk mail folders, as some e-mail servers will direct these messages there.
If you still can't find the confirmation code and your still having this problem, check with the network's help channel, usually #help and let them know.
