Soundhack is the right application for changing text files or whatever files into noisy sound files. i just opened the max463reference.pdf in soundhack and made it into 24bit aiff noise file in under 30 seconds. Very recommended.
the opensource program audacity let's you do this as well.
for something related - i saw a patch that read raw bytes, each bit in the byte corresponded to one of the 8 diatonic tones in a scale. 1 means play, 0 means don't play. Cool way to make music out of any kind of computer information.