Excalibur is a free open source TeX/LaTeX-Aware spelling checker. Still, it will also check the spelling in plain text documents. The new Excalibur release fixes a bug that could cause Excalibur to hang when there was a syntax error at the end of a file.
A powerful application that allows users to edit TeX files.
It can check your online communication.
Latexian is a handy LaTeX editor application for the Mac.
A powerful tool for testing your spelling skills, complete with Hangman game.
Open source spelling service for Mac OS X based on Hspell.