Radio Shack used to sell a voice chip in a kit that let you record and play
back either 10-15 seconds of audio, or another one that I think could have 4
messages up to 5 seconds each. All you had to do was add a battery. Many
modified this into an
enclosure with relay for PTT for a one-button voice keyer. I think the chip
is still available, but not from Radio Shack.
Try some of the electronic supply houses.
You could probably easily then make the
interface from the pc to the voice kit.

Alternatively, there are a number of logging
programs that have the capability for voice
keyers right in the software. I think Logger
and N1MM are 2 of them, and N1MM is
free. N1MM is a contesting software being
developed by N1MM, but a also a group
effort. Keying is CW, voice, Data modes.
Visit n1mm.com.

Good luck.
Bennett ko2ok.