Well, let's start with some programs, shall we? :3
You can use Photobucket. Photobucket is a very basic editor. If you have an account at photobucket.com, you can use it for free. You may want to start here and play around with it for a while.
You can download GIMP - it's a free art program. It's comparable to Photoshop. I have GIMP, but however, it is very complicated and difficult to use.
I've also heard of Photofiltre. It's similar to GIMP, and is also a free download. I do not have this downloaded, but I heard that it is much easier to figure out than GIMP.
Then there is Photoshop. Photoshop is the most advanced image editor out there, and is very popular, especially to hardcore photographers. Unfortunately though, it is not free, and must be purchased. D: I've heard that it's very expensive. I haven't looked up any prices though. [ Google it, maybe? ]
I'd start with Photobucket. Make an account there, and upload some photos. Then you can edit them. There are a varity of options there - you can resize your photos, crop them, or use the 'auto touch up' feature to clean it up a bit. There are a ton of coloring options - you can make the colors sepia, greyscale, neon... just play around with the different options. Some of them are really neat. :3
You can also add different text to your image through Photobucket. You can color on your image as well.
There are more advanced options, where you can color only specific areas, and make certain areas black and white, etc.
So, my advice is you start playing around on Photobucket, to start. If you have any specific questions, lemme know. I'd be happy to help. ;D [ And don't worry, I'm a failure at editing. I haven't done much of it, and I honestly am not too interested in it at the moment. ]