Woah, quick response! Thanks.
I would like to be able to preview latex equations as I'm writing. I really like writing latex, but can't wrap my mind around all the brackets in latex equations. There is a service called "equation service". In the text editor, you highlight the text you would like previewed and call the equation service. It cuts the highlighted text into the clipboard, turns it into a pdf, and then copies this into the clipboard and pastes it into your document. The result is that you see a typset equation rather than a mess of latex code. When it creates the pdf, it stores the latex code you orignially typed in the pdf. This way, equation service can be recalled on the pdf preview, this time replacing it with the orignal latex code so you can edit it.
Under emacs this functionality is provided by an addon called preview-latex which is brilliant ( http://preview-latex.sourceforge.net/ ). However, I'm fed up with emacs and would like to try a cocoa based editor, as they are way more easily applescripted.
The webpage for equation service is http://www.esm.psu.edu/mac-tex/EquationService/
- Rob
P.S. (I may have imagined PDF Replacement Services. The equation service home page talks of a program either supporing or not "text -> PDF services". I have looked on apples developer site and found no reference of this.)