http://www.asahi-net.or.jp/~ey5k-myhr/fx602p_e.htm These are the English pages of a Japanese site on the FX-602P. It has some interesting challenges on it. It also has the accolade of being the largest referrer to this site before the search engines logged it.
http://www.hpmuseum.org This site has
absolutely nothing to do with the Casio FX-502P but is definitive site for old
Hewlett Packard calculators