Maybe a bit late to revive this thread but I managed to compile pd-vanilla om my n900. Sound (alsa) does work but only at a samplerate of 11025 and with a delay of 600 msec.

I read on the pd mailinglist that they are working on better sound.

Sometimes after using pd I have to reboot my device because maemo cannot make any sound anymore though.

This is Pd version 0.42-6