You can edit verilog in anything.
I just wanted an editor. Will check out BBeditor. Thanks guys.
You may also want to take a look at the DVT Eclipse IDE from AMIQ. DVT supports e, SystemVerilog, VHDL and provides much more functionality then syntax highlight. like auto-complete, hyperlinks, class and module browsing, design hierarchies, diagrams, code refactoring, and more. There are guys happily working with it on mac.
For academic purposes you can get a free license, just fill in a form.
Just download a distribution for MAC from here:
http://www.dvteclipse.com/install_distribution.html
You should try TextWrangler which is BBedit's little brother. It is free from the Mac App Store. You can use any of the language modules for BBedit from http://www.barebones.com/support/bbedit/plugin_library.html with TextWrangler. I have both Verilog and VHDL language support installed in TextWrangler on my Mac. It's also a very good programming and general text editor.
What are you using to compile/run Verilog on your Mac? Is there anything close to Xilinx ISE that you have found?