Grammarly
http://bit.ly/GrammarlyProofreading
Free Writing and Proofreading software
In the publishing industry, Grammarly is the world’s best known automated proofreading program. It’s used by authors, business people, and anyone who needs their communication to be flawless. It checks for hundreds of errors not only in spelling, but also grammar and punctuation. It will also help with repeated words by making suggestions that will expand the vocabulary used.
Part of the reason Grammarly is so successful (beyond that of other proof reading software) is that its algorithms can pick up errors in the text and suggest context specific corrections. Were, we’re, and wear are all spelled correctly, but in different contexts they are certainly not all interchangeable. The sentences “We’re going to the store,” and “Were going to the store,” both contain correctly spelled words, but only one has the appropriate word choice for the context.
Grammarly has both a free version and a paid version, but for most authors, the free version is more than sufficient.