Here just a selection of links on the subject of pi.
Wikipedia
Information on pi may be found in the online encyclopedia at
www.wikipedia.org
Friends of Pi
„The goal and task of our group is to hold high and further the spirit of pi.“
http://pi314.at
The History of Pi
A thesis from a mathematics faculty on the history of the approximation of pi.
http://magnet.atp.tuwien.ac.at/scholz
English-language website
Article on how to calculate pi to the 1-millionth decimal point using a computer.
www.cecm.sfu.ca
Pi Search
Website where one can search for numbers occurring in the first 3.2 billion decimal places in pi.
www.pisearch.de.vu