Hi, this mail is to inform that Bill Schottstaedt just put up documentation for the snd pd external in the snd-manual:
http://ccrma.stanford.edu/software/snd/snd/grfsnd.html#sndwithpd
The documentation also also contains a screen-shot of a pretty neat stochastic pd patch made by Bill Sack, which use the snd external.
If you know (and like) lisp, pd and snd, you should check this out...