Just wanted to pass along a little trick that I use when writing software. About half of our 600 monitors are still 1024x768. We don't replace monitors until they are dead as good custodians of taxpayer dollars, and LCD panels are lasting many years. Usually IT developers have wide screens and some of them have dual monitors. It's easy to forget about the rest of our users, and suddenly software is developed that doesn't fit on their screens. Nothing worse than having to re-engineer a beautiful UI after finding this out during beta testing.
So what I always do is use my handy wallpaper that has a black box drawn at 1024x768 for testing screens.