This short video tutorial shows you how to achieve a look similar to the image I posted here last week. I used Lightroom 3 to do the work, but if you shoot RAW images, you could do this in the Camera Raw plugin in Photoshop. Aperture could be used to achieve a similar look as well. Some of the things I do in the video can be done in other apps as well. iPhoto has some similar tools to edit photos and while they might not give as much control, the idea that you can easily tweak a photo to give it a dramatic push is the same. One other app to check out is Flare, an inexpensive photo editor for Mac users, which has an interesting way of letting you try edits and effects without destroying your original.
Best viewed full screen.
Any questions? Hit me in the comments.