Register
 
 Usage:     /MSG NickServ REGISTER <password>
 Example: /MSG NickServ REGISTER mypassword

This command registers your current nick with NickServ.  After you have entered this command and received the confirmation notice, you are the owner of the nick, as far as NickServ is concerned.  The password can be anything you want, but make sure you remember it.
When you register, NickServ will add your current address ([email protected]) to the access list for that nick.  (The access list is a list of addresses that are allowed to use your nick.)  See the ACCESS command for information on how to add and remove entries from your access list.
NickServ registration lasts for 25 days if you dont go regularly to IRC.

Drop
 
Usage:     /MSG NickServ DROP <nick>
Example: /MSG NickServ DROP MarkP

This command cancels the registration of your nick, so you no longer control it.  Therefore, anyone can once again use your nick, and anyone else can register it as their own.  Before you use this command, you must identify to NickServ using your password.

Identify
 Usage:       /MSG NickServ IDENTIFY [nick] <password>
 Examples: /MSG NickServ IDENTIFY mypassword
                   /MSG NickServ IDENTIFY MarkP mypassword
 

If NickServ doesn't think you are allowed to use the nick, you must use this command to tell NickServ that yes, it is your nick.  You can identify for nicks other than the one you are currently using by specifying the nick you wish to identify for, as shown above.

Set Kill

Usage:     /MSG NickServ SET KILL <ON|OFF>
Example: /MSG NickServ SET KILL ON

If you want to make absolutely sure that nobody else uses your nick, the Nick Kill Enforce option is what you're looking for.  With this option set to ON, any user who isn't in your nick's access list will be forcibly removed from IRC, unless they give your password with the IDENTIFY command.  It is recommended that you set this option on, to lessen the chances of other people being mistaken for you.
 

Set NoMemo

Usage:     /MSG NickServ SET NOMEMO <ON|OFF>
Example: /MSG NickServ SET NOMEMO ON

Turning this option on prevents people from sending MemoServ memos to that nick.  This is useful if you will be away from the IRC for a long period of time, and don't want your memobox to fill up, or don't like memos for whatever other reason.  If you have this turned on, the following line will be added to the end of you NickServ info:

 Set URL

 Usage:        /MSG NickServ SET URL [URL]
 Examples:  /MSG NickServ SET URL http://www.mis.ca/dialin/pacman
                    /MSG NickServ SET URL mailto:[email protected]
 to clear it:   /MSG NickServ SET URL

Use this command to attach a URL to your nick.  The URL could be an email address, or a web page where people can find out more information about that nick.  This URL will be included in the information revealed by using the INFO command, and will also appear on the DALnet NickServ web page.

Set Passwd

Usage:     /MSG NickServ SET PASSWD [value]
Example: /MSG NickServ SET PASSWD mynewpassword

This command lets you change the password used to gain access to your nick.  Some people feel that you should change your passwords frequently, and it is always a good idea to change your password if you suspect someone else has been using your nick.  Remember that your password is case-sensitive, and don't forget that you've changed it.