Linear Network  
   Linear Logic in Computer Science is lead by the "Logic of Programming" research team. Its thematic is focused on developing the theory and the applications of Linear Logic. It is formed by seven sites located in Marseille, Bologna, Cambridge, Ed
   http://iml.univ-mrs.fr/ldp/LINEAR/

Mathematical Reasoning Group  
   Research group based in Edinburgh, it is running on the interaction between logic, mathematics and informatics. Links to publications, homepages, reports.
   http://dream.dai.ed.ac.uk/

Logic of programming  
   The "Logic of Programming" research team is interested in proof theory and its relations with theoretical computer science. The main topic is mathematical interpretation of proofs : nets (proof = graph), denotational semantics (proof = function)
   http://iml.univ-mrs.fr/ldp/welcome.html

The Epsilon Calculus  
   Discussion of David Hilbert's development of this type of logical formalism with emphasis on proof-theoretic methods.
   http://plato.stanford.edu/entries/epsilon-calculus/

Fast-growing Functions and Unprovable Theorems  
   Online seminar on Goodstein's Theorem, transfinite ordinals, formal number theory, Wainer Hierarchy of fast-growing functions, and the Kirby-Paris Theorem.
   http://www.maths.bris.ac.uk/~maadb/research/seminars/online/fgfut/fgfut09.html

The Calculus of Structures  
   The calculus of structures is a new proof theoretical formalism. It exploits a top-down symmetry of derivations made possible by deep inference.
   http://alessio.guglielmi.name/res/cos/index.html

ProofTheory.ORG  
   Basic material on proof theory and the home page of the only mailing list devoted to proof theory, with hundreds of experts.
   http://www.prooftheory.org/

Topics in Logic and Proof Theory  
   Brief introductions to combinatory logic, the incompleteness theorems and independence results, by Andrew D Burbanks.
   http://www.maths.bris.ac.uk/~maadb/research/topics/logic/

Proof Theory  
   Open Encyclopedia entry. Hierarchically organized by subtopics.
   http://open-site.org/Science/Mathematics/Logic/Proof_Theory/

G. Japaridze's Papers  
   Full list of publications by this author, with about 30 items in the area of proof theory. Many of the papers are downloadable.
   http://www.csc.villanova.edu/~japaridz/study.html

Frogs Discussion Group  
   Internet forum focused on the calculus of structures.
   http://news.gmane.org/group/gmane.science.mathematics.frogs/