http://www.vizef.demon.co.uk/
Home of many free, open source designs in VHDL.
http://tech-www.informatik.uni-hamburg.de/vhdl/vhdl.html
Information on conference 2003, conference archives, a special interest group and FAQ.
http://www.cadenceusers.org/
VHDL models from Mississippi State University
http://www.erc.msstate.edu/mpl/distributions/vhdl/
VHDL Simili a freeware VHDL compiler/simulator. It supports VHDL'93, Vital, and SDF. Support for Altera, Atmel, Cypress and Xilinx.
http://www.symphonyeda.com/
By Simucad. 64-bit Verilog HDL simulation products for FPGA and ASIC design and test. Included are a Verilog HDL Finite State Machine Editor, Waveform Viewer, and Chromocoded Text Editor.
http://www.simucad.com/
Directory VHDL tutorials, papers, examples, tools.
http://www.geocities.com/SiliconValley/Heights/8831/vhdlfpga.html
vhdl2c is a vhdl to `C' converter by Michael Knieser, based on Thomas Dettmer's yacc grammar for VHDL.
http://bear.ces.cwru.edu/tools.html