Sigasi HDT, which is an Intelligent Development Environment (IDE) for VHDL, now supports Mac OS X. Sigasi HDT is built on the Eclipse platform and contains an ultra-fast VHDL parser and compiler. As a result, the tool fully understands a design in terms of VHDL concepts. The tool is currently available in a public beta program. Sigasi HDT for Mac OS X is available now in the ongoing beta program.
More info: Sigasi HDT