RECTANGULAR SELECTION in all Leopard text editors

    Place cursor.
    Hold shift-option and move cursor to select a rectangle.
    Relocate cursor to destination.

Example: Move BBBB column between AAAA and CCCC.

    AAAA     CCCC
    This     This
    goes     goes
    on the   on the
    left.    right.

    BBBB     DDDD
    This     This
    goes     doesn't
    in the   go
    middle.  anywhere.

Place cursor just before BBBB.
Hold shift-option and move to just before “anywhere”.
Press command-X.
Relocate cursor to just before CCCC.
Press command-V.

Note. This is not in a text editor.