If those are your main or only platforms then SDL is probably your easiest and friendliest solution. I'm not partial to GLUT myself and it doesn't do everything that SDL is going to do for you. (controller/gamepad input, audio/music mixer, some texture loading routines)

Once you have a decent SDL base to work with the rest can be all OpenGL for your graphics. The NeHe tutorials can help you get started, but I'm not sure if they cover using SDL with OpenGL. SDL is in fact designed to use OpenGL instead for graphics, that's why they bundle it together.