LaTeX Editor for OS X

Just not to leave it unmentioned: one of the standard LaTeX editors/previewers for Mac OS X is TeXShop. Of course, one needs to be able to use LaTeX, but it streamlines the compilation, highlights syntax and generally helps. Of course, on tex.stackexchange.com, they'll be glad to help more.

I am guessing that you are saying is that LaTeX seems too difficult (or rather too complex) rather than that TextMate is too difficult to use.

If you want an editor that lowers the level of LaTeX knowledge you need to produce a document, I do not really think there exists one (i.e. you still have to compile and check for errors, solve bibliography bugs etc).

An option would be to write the document in MultiMarkdown which converts into LaTeX. You can do this in Scrivener which also happens to be a very good writing environment.

MultiMarkdown is a markup language that is quite intuitive and easy to read (in fact Ask Different uses Markdown (MultiMarkdown's parent) to format comments).

... otherwise there is always LyX which aims to be LaTeX but without the need to learn LaTeX, but you might run into stuff that you want to do, but can't.

Whatever you do, advise him or her to install MacTex - it is the easiest way to get LaTeX on your mac. By the way: The TeXShop mentioned my DaG is in that package, too.

But I agree with fnurl on that: As long as you write LaTeX, it will be "hard" to learn. No matter what GUI-Applications helps you. Because if you hide everything behind buttons, you loose LaTeX's advantage and you could be using Pages or Word instead.

There's a recent addition called Texpad available in the Mac App Store. Simple, streamlined and well-integrated with OS X.

Texpad is a LaTeX editor designed for straightforward navigation of projects of any size. When Texpad opens a document it scans through it, looking for LaTeX structure commands and any included files, then it presents you with an outline view with which you can swiftly navigate the entire project.

If you're looking to do homework or other more casual writing, try Archimedes: http://www.mattrajca.com/archimedes

It has great code completion support for mathematical symbols, includes an extensive math library, and even lets you enter mathematical symbols by drawing them on your trackpad!