Coloring Sky

[Nikon Fan]

I went out today and shot some pics at a local lake. The sky was great, clouds everywhere, but I really want to make them reddish or orange rather than bright blue. How in the world do I go about doing this??? I've been playing with the image, and also looking for a decent tutorial, but so far nothing has worked right. I got some great lookin blue tones in one pic, but I'd like to have a variety of color in some of the others...Thanks in advance for any help