You can get a decent Verilog simulator (Cver) from the EDA Downloads section of this web site
I am working on the Vide Verilog IDE and waveform viewer but I'm not finished with the port yet. You can see a screen shot at this URL. I have the simulator and waveform viewer working but there are still some bugs loading files in the Verilog editor.
Felix Bertram has completed a port of IVI to OS-X (IVIonOSX). IVI is a GPL'ed simulator frontend, to perform interactive VHDL and Verilog simulations, and waveform viewing.. This is the source for a GPL'ed VHDL and Verilog simulator and waveform viewer, shrink-wrapped as a ready-to-use installer for MacOSX. The goal of the IVIonOSX effort is to port the required tools to the Mac and maintain a reliable binary distribution that is as Mac-like as possible.
IVIonOSX currently integrates the following tools which are described in more detail below:
IVIonOSXis available here: http://ivionosx.sourceforge.net/
GHDL implements nearly all VHDL87 (common name for IEEE 1076-1987) standard, most features of VHDL93 (aka IEEE 1076-1993) and the protected types of VHDL00 (aka IEEE 1076a or IEEE 1076-2000). The VHDL version can be selected with a command line option. The current version is a beta version: some VHDL features, such as overflow checking, are not implemented. However, it is complete enough to compile the std_logic_1664 package or the vital packages. It have also successfully compiled and run DLX and leon1.
GHDL directly creates binaries or executable images, which is the best form for testbenches (ie autonomous self-checking VHDL designs which use assert). A binary can also creates a VCD file, which may visually be inspected with wave viewers.
DirectVHDL is a low cost VHDL simulator with the following features:
TkGateis a event driven digital circuit simulator with a TCL/TK-based graphical editor. TkGate supports a wide range of primitive circuit elements as well as user-defined modules for hierarchical design.