An Introduction to Programming Languages: Neutral conceptual analysis; useful for those who know one language and want to learn about others.
CodeComments Programming Languages Discussions: Web access to Usenet newsgroups of various programming languages.
Introduction to Programming Languages: By Anthony A. Aaby; 1996. Book, online only, draft version, no paper edition. Formats: HTML, PDF, PS, DVI, TGZ. [open content, Creative Commons License]
Lambda the Ultimate: Programming Languages Weblog with news and discussion.
PLNews: Programming Language News: News, articles, announcements and information focusing on programming languages.
Programming Language: Growing article, with links to many related topics. [Wikipedia]
The Retrocomputing Museum: Dedicated to programs that induce sensations that hover somewhere between nostalgia and nausea.The freaks, jokes, and fossils of computing history.
Webopedia: Programming languages related terms.