Paralyn Associates also provides proof-reading services. Primarily the review of technical documents and user manuals.
We've been doing this at our "day job" for years now, but have only recently realized that there might well be a need for this sort of service in the shareware and consulting communities. As such, we're not truly established in this area and haven't worked out a pricing structure as yet. Contact us and we'll look over your project and negotiate a price and schedule.