Average-Case Complexity Forum  
   Introduction and survey papers.
   http://www.uncg.edu/mat/avg.html

A Compendium of NP Optimization Problems  
   This is a preliminary version of the catalog of NP optimization problems.
   http://www.nada.kth.se/~viggo/problemlist/compendium.html

ECCC - Electronic Colloquium on Computational Complexity  
   A forum for the rapid and widespread interchange of ideas, techniques, and research in computational complexity. Research reports, surveys and books; meetings, discussions and web resources.
   http://www.eccc.uni-trier.de/eccc/

Roberto Bayardo's Resources  
   Includes the relsat SAT solver and related papers.
   http://www.almaden.ibm.com/cs/people/bayardo/resources.html

SAT Live!  
   A collection of up-to-date links about the satisfiability problem (solvers, benchmarks, articles). A discussion forum is available as well.
   http://www.satlive.org/

SATLIB - The Satisfiability Library  
   A collection of benchmark problems, solvers, and tools. Provides a uniform test-bed for SAT solvers as well as a site for collecting SAT problem instances, algorithms, and empirical characterisations of the algorithms' performance.
   http://www.intellektik.informatik.tu-darmstadt.de/SATLIB/

Stas Busygin's NP-Completeness Page  
   A proposal for solving NP-hard problems.
   http://www.busygin.dp.ua/npc.html

Computability and Complexity  
   An online course on complexity.
   http://www.csc.liv.ac.uk/~ped/teachadmin/algor/comput_complete.html

Information-based Complexity  
   People, publications, prizes.
   http://www.ibc-research.org/

Constraint Satisfaction Problems  
   Research group in the Computing Laboratory, Oxford University.
   http://web.comlab.ox.ac.uk/oucl/research/areas/constraints/index.html

Parameterized Complexity  
   Brief description, list of workers and problem compendium, compiled by Todd Wareham.
   http://www.cs.mun.ca/~harold/W_hier/W_hier.html

Probabilistically Checkable Proofs and Approximation  
   Pointers to some survey articles and their authors, by M. Bellare.
   http://www-cse.ucsd.edu/users/mihir/pcp.html

Algorithms and Complexity Research Area  
   The Oxford University Computing Laboratory's area on Algorithms and complexity, with links to lectures and information.
   http://web.comlab.ox.ac.uk/oucl/research/areas/algs/

Complexity of Algorithms  
   A list of topics from a Computer Science course involving complexity of algorithms. HTML and PS format.
   http://artemis.cs.yale.edu/classes/cs460/Spring98/contents.html

Algorithms and Complexity  
   An overview of computational models and methods and how they relate to complexity, with links to selected papers.
   http://www.almaden.ibm.com/cs/k53/algo.html

Computational Complexity and Programming Languages  
   Summaries of talks of the DIMACS workshop (July 1996), collected by James Royer.
   http://www.cis.syr.edu/people/royer/talks.html

Computational Complexity Theory  
   Definition of the subject, links.
   http://www.cs.umass.edu/~immerman/complexity_theory.html

P vs NP  
   Official version of the million dollar open problem in Theoretical Computer Science by the Clay Mathematical Institute.
   http://www.claymath.org/millennium/P_vs_NP/

Complexity Theory  
   Two set of lecture notes by Prof. Oded Goldreich, Weizmann Institute.
   http://www.wisdom.weizmann.ac.il/~oded/cc.html

Lecture notes on Complexity  
   Collection of lecture notes by Prof. Eric Allender, Rutgers University.
   http://athos.rutgers.edu/~allender/lecture.notes/

Challenging Benchmarks for SAT and CSP  
   Includes related links, references and a summary of the results for the SAT benchmarks used in SAT Competition 2004.
   http://www.nlsde.buaa.edu.cn/%7ekexu/benchmarks/benchmarks.htm