From LSWiki
[ The Mail ]
The mail is a service provided to all by the Adventurer's Guild, taking advantage of the close communication maintained by the widespread Guild to create an effective message delivery system. To use the mail, simply go to any hall of the Adventurer's Guild and use the following commands:
read mail Displays the full mailer interface. from Displays whom your mail messages are from. mail <name> Send a piece of mail to <name>