IPoding reports on MaP3, which uses Text-to-Speech to convert driving directions into MP3 files. From Map3’s website:
MaP3 will give you the best driving route to take between any two addresses in the United States and Canada. While there are other websites that give driving directions, MaP3 is the only website that gives them to you as spoken directions, delivered in MP3 format to your email inbox! Instead of reading your directions as you drive, you’ll be listening to them on your MP3 player or, by burning them to a CD, in your car’s stereo deck!
MaP3 provided a sample to IPoding you can listen to. Definately a cool idea, but you’ll need cat-like reflexes to keep up with the spoken directions.