Not everybody can afford to run out and get their hands on a copy of PhotoShop or Paint Shop Pro. ((Even some of us who have it didn't necessarily get it the most honest of ways.))
But no fear! There are plenty of different ways that you can get your hands on some photo editing programs and software for free!
One popular freeware program that you can download is called GIMP, or GNU Image Manipulation Program. You can download it here, on their website. It's a very user-friendly program made for simple–and sometimes not-so-simple–graphic design and photo editing.
Another program you can use is actually available online, Photoshop Express. This can be found over here. It's a simplified Photoshop, available on your browser. There's a very thorough tutorial on the first page, to walk you through the website, and help you familiarize yourself with the workings in there. Simple, simple stuff.
For those of us who use Flickr, even it has its own internal photo editing software! Flickr utilizes a program called Picnic to help edit the photos that you upload. I'm currently in the process of putting together a quick tutorial for using Picnic. I promise, it's INCREDIBLY easy, very user-friendly, and convenient to use within Flickr!
Is there anything out there that you know of that I've missed? There are SOOO many different resources out there, these are just a few, and I know there are people out there looking!
List other sites that you know of here in the comments or over at our forum, so that others can take advantage of them too!
Kayla is a mildly hairbrained, but incredibly loved mom who tries to live life to it's fullest, one day at a time!! You can catch more of her ramblings over at A Glance Into A Mom's World.

Kayla, I use the FastStone Image Viewer, which can be downloaded at http://www.faststone.org. You can do lots of stuff with it, such as crop, "mess" with brightness, contrast, etc.
Do you know of a free program that allows you to clone?
Picnik is another popular free service, as is Picasa (from Google)
just a quick correction. The flickr editing site is picnik.com. And I highly recommend it. Super easy to use