Copy-editing site and test
Came across this site by Trevor Horwood, a freelance proofreader and copy editor in Britain. Worth taking a look at. Sure, as he notes, there are more than a few language differences across the pond, yet his proofreading test also proves there are a lot of shared "truths."
(And besides, with all the outsourcing and globalization going on, who knows where you'll be working next week?)
A good site to visit.