Removing part of a picture on gimp?

I have a couple pictures that I'd like to edit parts out of. For example, a picture of one horse with another horse's hing leg and tail in it. I primarily use gimp to edit my pictures, but I'm still fairly new to it. I was wondering if there's a way I can edit out parts of the picture, and if so, how?
By the way, I already know you can use the color picker thing and then paint over the area where image you want to remove is. Is that the only way?

Have you tried the clone stamp. You pick an area similar to the area you'll be painting over kinda, then it copy's what you have chosen. I'll try explain it better in a minute.

Hmm... That would make sense. But I can't seem to figure out how to use the cloning stamp... When I click it it won't let me copy the image.

If you hold down ctrl then click on the area you want to clone, that sets you up for cloning that selected area then just normal click what you want to draw over.

Here's an image I quickly edited using the clone tool, you might also find that using the clone tool leaves the image a bit patchy so using the healing tool can help, it works similarly as the clone tool.

Thanks!! That's what I had been doing, it wouldn't work. But I just reopened the same picture and it worked just fine. Here's what I got
Original- Edited - Edited very badly because I got lazy ;)

They look great, I do, quite like the last one :)

Thank you I have another question as well, maybe you can answer it... In the toolbox, part of mine dissapeared. Normal toolbox looks like...
Google Image Result for http://www.toontowncentral.com/gallery/data/1416/GIMP_toolbox.png

But mine doesn't have from "rectangular select" below. It just says "you can drop dockable dialogs here" I've tried googling it for instructions on how to change this and that didn't really help. I also tried uninstalling and reinstalling gimp and it reinstalled the same way. There's got to be some simple thing I'm missing to get it back... Any ideas?

Have the windows drop down list at the top and then on to dockable dialogs, then click tool options then I think another window will appear if you drag that across on to the place where your tool options would usually be

I tried it... It won't let me drag the tool options item under the windows tab. :/