[Gimp-user] sky question

[Joel Glanfield]

Hello,

First time poster here.

Just curious about how to change sky-colors like you see in a lot of 
professional photographs. For example, on this site:

http://www.novascotiaphotos.com/

...the banner at the top has purple sky, and there are several photos in 
the gallery with different sky-colors. What's the best way to go about 
doing this using the GIMP? I've been doing some googling, but I'm 
probably using incorrect search terms since I haven't really found 
anything helpful (yet).

Any replies are appreciated!

Regards,
Joel