Verilog
A Brief Introduction to PLI, Alternate Verilog FAQ, Asic Tools, ASIC World, Celia's Verilog and EDA, Converter from verilog to html, Doulos KnowHow - Verilog Models, Handbook on Verilog HDL, Hello, World program, International Cadence Usergroup
VHDL
Tools, Alternative System Concepts, Inc., Amontec VHDL Window, Andy Rushton - VHDL for Logic Synthesis, CAST, Inc., comp.lang.vhdl archive, CQPIC, Doctor VHDL Design Services and Training, Doulos KnowHow - VHDL Models, Emacs VHDL Mode, Free Model Foundry: FMF
ABEL Primer
Overview of the ABEL Hardware Description Language.
Doulos KnowHow
Designer's guides and models for VHDL and Verilog. SystemC home. Also Perl and Tcl/Tk for hardware designers resources.
ForSyDe
The ForSyDe (Formal System Design) methodology has been developed with the objective to move system design to a higher level of abstraction and to bridge the abstraction gap by transformational design refinement.
HDL at Wikipedia
Definitions, resources, and links related to hardware description languages.
Ruby
Ruby is a notation and design discipline intended for the development of regular integrated circuits and similar hardware and software architectures.
Sim-nML
A high-level processor specification language. it views a processor as a machine that executes a set of instructions. syntax, image, functionality (side-effect), resource-usage and timing of each instruction are described in a hierarchical form.
Titivillus: Software Development
Links to many programming languages, including several HDLs.