NickServ allows you to "register" a nickname and prevent others from using it. The following commands allow for registration and maintenance of nicknames; to use them, type /msg NickServ command. For more information on a specific command, type /msg NickServ HELP command.
CONFIRM - Confirm a nickserv auth code
RESEND - Resend a nickserv auth code
REGISTER - Register a nickname
GROUP - Join a group
IDENTIFY - Identify yourself with your password
ACCESS - Modify the list of authorized addresses
SET - Set options, including kill protection
SASET - Set SET-options on another nickname
DROP - Cancel the registration of a nickname
RECOVER - Kill another user who has taken your nick
RELEASE - Regain custody of your nick after RECOVER
SENDPASS - Forgot your password? Try this
GHOST - Disconnects a "ghost" IRC session using your nick
ALIST - List channels you have access on
GLIST - Lists all nicknames in your group
INFO - Displays information about a given nickname
LIST - List all registered nicknames that match a given pattern
LOGOUT - Reverses the effect of the IDENTIFY command
STATUS - Returns the owner status of the given nickname
UPDATE - Updates your current status, i.e. it checks for new memos
GETPASS - Retrieve the password for a nickname
GETEMAIL - Matches and returns all users that registered using given email
FORBID - Prevents a nickname from being registered
SUSPEND - Suspend a given nick
UNSUSPEND - Unsuspend a given nick