There is a "Game of Life" tutorial at http://tryapl.org, which allows you to step through the game of life expressions interactively.
Good places to start learning about APL are the Vector website (run by the British APL Association) http://www.vector.org.uk where there is a list of current APL books, the APL Wiki at http://aplwiki.com/ , and the Dyalog website http://www.dyalog.com which has links to for obtaining a personal (non-commercial) licence for our APL interpreter if you like learning by doing :) There are also links to some forums and discussing groups on both sites where you will find people who know APL inside and out...