The Retrocomputing Museum - http://www.catb.org/~esr/retro/ Dedicated to programs that induce sensations that hover somewhere between nostalgia and nausea.The freaks, jokes, and fossils of computing history.
Webopedia - http://webopedia.com/Programming/Programming_Languages/ Programming languages related terms.
An Introduction to Programming Languages - http://www.acooke.org/andrew/writing/lang.html Neutral conceptual analysis; useful for those who know one language and want to learn about others.
Introduction to Programming Languages - http://cs.wwc.edu/~aabyan/PLBook/ By Anthony A. Aaby; 1996. Book, online only, draft version, no paper edition. Formats: HTML, PDF, PS, DVI, TGZ. [open content, Creative Commons License]
Programming Language - http://en.wikipedia.org/wiki/Programming_language Growing article, with links to many related topics. [Wikipedia]
PLNews: Programming Language News - http://plnews.org/ News, articles, announcements and information focusing on programming languages and their implementations.
Lambda the Ultimate - http://lambda-the-ultimate.org/ Programming Languages Weblog with news and discussion.
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