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Uh... typically the PhD is where you start getting teaching experience. At least in Italy. Non-PhD's can volunteer to "assist" in some laboratories through "150 hours" programs, but that's it.
Well it's as close as "live LaTeX" as it gets currently. I dunno about OSX but I've found out LyX is satisfactory for taking lecture notes (...that means notes during others' lectures right?) even when they involve a lot of maths.