This MacWorld article relies on Photoshop for most of its fixes. I liked it because it puts some moderately advanced image editing features in a problem solving context: Macworld: Feature: Emergency fixes for bad photos. Once I buy Aperture, it will be interesting to see how many of these fixes can be implemened in Aperture. The thing I most need to learn is how to rescue underexposed regions without blowing out highlights. I hate to think I have to buy Photoshop Elements, it's a notoriously ill-behaved OS X application (won't install/run except as Administrator, an egregious flaw).