Help for SET PROPERTY:

SET PROPERTY manipulates metadata
associated with an account.

To delete a metadata entry, specify
the name and leave the value blank.

Syntax: SET PROPERTY <name> [value]

Example:
    /msg &nick& SET PROPERTY URL http://www.example.com/~jay/
    /msg &nick& SET PROPERTY SIGN Pisces
    /msg &nick& SET PROPERTY ICQ