1. An apparatus for use with a computer and an existing computer keyboard associated with said computer, and inserted serially inbetween said keyboard and said computer, for storing and executing programmed keystroke sequences, said apparatus comprising: a computer program adapted to recognize a start programming code generated by depressing a first predetermined key of such existing keyboard, wherein said first predetermined key represents a command to initiate a MACRO programming sequence; said computer program further being adapted to recognize an end program code generated by depressing a second predetermined key of said existing keyboard, wherein said second predetermined key represents a command to end said MACRO programming sequence; a controller in communication with said keyboard and responsive to said computer program, said controller being responsive to said start programming code entered by a user at said existing keyboard to signal the start of said MACRO programming sequence in which at least one user selected key of said existing keyboard is defined by said user to represent a plurality of keystrokes, said plurality of keystrokes representing a user command, and said controller further being responsive to said end program code to signal the end of said MACRO programming sequence; and a memory for storing a first code corresponding to said selected key and a plurality of second codes corresponding to said plurality of keystrokes such that said controller recalls said second codes from said memory when said user selects said selected key and transmits said second codes representing said plurality of keystrokes to said computer from said existing computer keyboard.