The pack includes a set of 8 sky textures and 2 extra bonus panoramic sky textures. These can be used for whatever you consider fit.
You are not allowed to redistribute or sell these resources as your own because they belongs to me. I give everyone full permission to use them in both commercial and non-profit work, without asking anything in return.
It would be nice if I could see how and where you used them and I encourage you to leave me a link with your finished work and/or link back to my website from the place you posted the original work, however, this is not mandatory, it is just appreciated and I would consider it a sign of common courtesy.