i think i got this off apple.com
on open (f)
set voice_names to {"Agnes", "Albert", "Bad News", "Bahh", "Bells", "Boing", "Bruce", "Bubbles", "Cellos", "Deranged", "Fred", "Good News", "Hysterical", "Junior", "Kathy", "Organ", "Princess", "Ralph", "Trinoids", "Victoria", "Whisper", "Zarvox"}
open for access f
set s to read f
close access f
set this_voice to (choose from list voice_names default items "Agnes" with prompt "Pick the voice to use:") as string
say s using this_voice saving to (choose file name with prompt "Save As..." default name "untitled.aiff")
end open
just save that as an application and drag a text file onto it