Generate LAME-encoded audio MP3 from text – Mac OS X Hints
http://hints.macworld.com/article.php?story=20040926192411975 also, afconvert (which is built in), viz:
http://apple.stackexchange.com/questions/26099/is-there-a-way-to-convert-audio-files-in-mac-os-x-or-the-command-line-without-us then push onto iphone wirelessly
http://www.pcmag.com/article2/0,2817,2407487,00.asp
say -v Vicki -f a.txt -o a.aiff
afconvert a.aiff -o a.m4a -f m4af