Good proofreading site?

We don't have any natural english speakers with our company, so what is a good site to have our blog posts, etc. proofread for style, grammar, etc?
Any comments and thoughts on the subject are appreciated.

In the past, I have used http://www.theproofreaders.com to proof our copy and the results have been acceptable.

PaperRater.com. Highly recommend, have tested essays with this site, and does the job well and free! All online and no downloads...

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I'm going on vacation until May 25th. But I'd be happy to help proofread your site for you as I'm sure others would be as well. I think it's a bit silly to pay people/services that much to proof read unless it is a lot of paper work like 100+ pages or non-standard or legal documents.

Not necessarily proofreading, but a spell checking (which is a part of proofreading) site: http://www.spellr.us/

I have used http://www.wordy.com, excellent site quick, cheap and very accurate well worth checking out

Have a look at Peopleperhour. Its is a very large community of free-lancers and at last count they had 2,069 freelance professionals who do proofreading. You have to pay them but the quality should be a lot more consistent than what you could get for free.