The Association of Lisp Users: ALU - This well organized site presents over 100 printed pages of information about Lisp, including references, books, tutorials, free and commercial implementations, free software, and other resources.
Franz Inc. - Producers of Allegro CL and related products
LISP.de - Lisp User Group based in Germany
John McCarthy - The home page of the creator of Lisp.
CMU Artificial Intelligence Repository - Collection of files, programs, publications, of interest to Artificial Intelligence researchers, educators, students, practitioners.
Gordon S. Novak Jr. - Free software, information, links.
P.S.: "Parenthetically Speaking" - A set of articles concerning various aspects of the Lisp family of languages
Werkowski's Lisp Page - Information on CMU Common Lisp system and a port to Intel x86 architecture.
pLISP - An experimental implementation of reflective functional programming. It is built as a hybrid architecture using a simple Lisp interpreter for driving the compiler and wrapping calls to the Graph-reduction VM.
Paul Graham - Lisp code, articles (including Beating the Averages), and a big collection of links.
CMPnet TechWeb TechEncyclopedia: Lisp - Great resource: over 11,000 definitions.
Successful Lisp: How to Understand and Use Common Lisp - Excellent online book by David B. Lamkins about beginning to learn Common Lisp.
Lisp: Good News,Bad News, How to Win Big - Lisp has done quite well over the last ten years: becoming nearly standardized, forming the basis of a commercial sector, achieving excellent performance, having good environments, able to deliver applications. Yet the Lisp community has failed to do as well as it could have.
SHELF by Applixware - Applixware's LISPy extension language, now decoupled from their software.
Hello, World program - Lisp
newLISP for Linux and Win32 - newLISP is a Lisp dialect close to Scheme but with dynamic scoping. The GUI version features an IDE with editors and a source level debugger. The Linux version is licensed GPL.
Screamer Tool Repository - Common Lisp extension that adds support for nondeterministic programming, and on top of this substrate, provides a comprehensive constraint programming language to formulate and solve mixed systems of numeric and symbolic constraints.
God Wrote in Lisp - Humor lyrics and MP3, evangelising Lisp.
Lisp Resources - Links to Lisp information and software.
PC AI: LISP Programming Language - Very useful page of links with good helpful annotations for vendors, search engines, more: references (linked and non-linked) for articles, books.