23. A pen based computer system for interaction with pre-printed material comprising: a processor; a memory coupled to said processor and for storing audio content that is associated with positions of printed material; an optical detector coupled to said processor; said processor for receiving input from said optical detector to determine a position of said pen based computer system over printed material comprising a position code responsive to an interaction of said pen based computer system and said printed material; an audio transducer for producing audio output under control of said processor; wherein said pen based computer system is capable of producing audio output corresponding to said position contemporaneously with said interaction, and wherein said audio output further corresponds with other positions that were not previously determined by said pen based computer system.
28. The pen based computer system of claim 23 further comprising a user operable button to command said processor to produce audio output corresponding to text of said printed material without reference to said printed material.