There are a few freebies you can download from the Internet but at some point, if you are serious about photography you are going to have to invest in Photoshop or something equivalent. Personally, I think Photoshop reigns King. I have both Elements 6 and CS3. CS4 is out but I have heard some negatives and will stick with CS3 for now.
People who know little about photography think of Photoshop only as a means of doctoring a photo by dragging things into the photo that originally weren't there or taking things out such as power lines or some one's ex-husband. That is not the purpose of Photo editing at all. Nothing is sadder than to discard a good photo because it is badly exposed. So much can be fixed as seen in the before and after of the photos below.

Photoshop or photo editing software is the digital photographer's dark room. It is a must for any serious photographer to learn and be skillful at photo editing. If you learn nothing else in Photoshop learn how to re size and crop a picture, change the exposure by adjusting the levels, increase and decrease the saturation, and increase and decrease the contrast. These are the same things a Photographer did in the dark room with film.
Also, one final tip - always save a copy of your original photo before editing... meaning you will
