The Free IP project supports open hardware designs by freely releasing core systems in HDL.
OpenCores has many actively developed cores available.
FPGA CPU News is a site devoted to discussion and support of the "eXtensible System On a Chip", a 16-bit CPU core written in Verilog.
The GNU EDA project is building a completely open Electronic Design Automation environment from parts written by several authors. As the focus is on reconfigurable systems, schematic capture and Verilog simulation and synthesis are key elements of this system.
For custom chip design, Static Free Software has released the Electric design environment.
You can get an entire Sparc V7 processor in VHDL from the European Space Agency.
For the more practically-minded, there is a PIC 16C57 core available in Verilog.
Tom Walsh's EZ328SIMM was an inspiration to use the MC68EZ328 Dragonball processor in our own designs, including Pengachu and USS (old).
13 Nov 2000