Beej's Guide to Unix Interprocess Communication is a very well-written introduction to Unix IPC. Examples are in C with the standard Unix C functions, but many of the descriptions should apply to Unix IPC in other languages.
This is BrainLog, a blog by Dan Sanderson. Older entries, from October 1999 through September 2010, are preserved for posterity, but are no longer maintained. See the front page and newer entries.
November 1, 2001