I'd like to make the next project I publish available in e-book and paperback.

Does anyone know whether I can use a cover I designed with a CreateSpace template to print through Lightning Source as well? I'd like to do my own cover with Gimp, but could really use a template to get the dimensions right for printing. Or is there a way to get Amazon to carry a book that's printed through Lightning Source?

What's the best way to make a POD paperback available through as many online retailers as possible?

Thanks in advance for your help!