Except for the ones noted above, there is the Japanese installation page at http://www.rinc.or.jp/~kotobuki/gem/index.htm

There is a Pd mailing list. Subscription info is on IEM's site

One of pd's unofficial home-pages is at http://pd.iem.at hosted by the Institute of Electronic Music and Acoustics, Graz, Austria

Also hosted by the iem is the site of the pd-community

An interesting place might also be Guenter Geiger's site

there are lot's of other cool pages (search the net...)