I'm looking for an editor like tikzedt for Mac OS X. Or something similar in order to write and see quickly the result.
Any suggestion ?
I think TikZ-Editor is what you are searching for. It has a beautiful Mac-ish interface and the same features as tikzedt.
And just to complete the list – I used Latexian before, it also provides live preview and an even better interface. You can use Latexian for editing full LaTeX-Files, too.
Edit: As I just saw, there is no WYSIWYG-Editing in TikZ-Editor...
(I know an answer has already been accepted, but I can't pass over this editor)
Another very good editor is Latexit. Its main purpose is to write equations that can then be sent to other applications, but it has many other uses. I use it to draw my tikz pictures. It is easy to use. In addition it has a library, where you can store all of your art and reuse it later. Once your picture is complete you can paste the code into your TeX document, or save it in many different formats.
This is really a non-answer, but now a year after the original question was posed, I think it is important to make a comment. I've tried TikZiT and TiKZ-Editor, but unfortunately, both these programs are still very limited. I gave up and ran Parallels Desktop and TikZEdt and have to say that this Windows version is far superior than the alternatives on OSX.
It is a pain to run a virtual desktop, but I think in this case it is worth it, assuming you have access to Windows and Parallels.
Sourceforge is misbehaving at the moment, so I can't post a new release of TikZit. In the mean time, here is the version I use:
It works on Mavericks, but I haven't tested on Yosemite. The latest version in the repo doesn't build on Mavericks however, because of this ARC issue some people have already pointed out. Hopefully we'll have that sorted out soon.