I just found this extensive tutorial (though quite old already) on Cycling ’74 ‘s website (they sell and develop Max/MSP, Pd‘s ancestor, originally created by Miller Puckette while working or studying at IRCAM in Paris, France – incidentally, Max/MSP has been used by Radiohead‘s lead guitarist Jonny Greenwood, first on the Hail to the thief album, for many years. I discovered Pd while searching the web for a free equivalent of Max/MSP – I thought that if Jonny was interested in it then it had to be something worth exploring).
It’s probably worth a read. When I have time I’ll probably write a longer post about it (I’m expecting there to be nice patches worth replicating in Pd).
Guitar Extended 
Thanks! sure, I want to sound like Jonny too!
🙂