How do I make a modern(ish) map with photoshop?

[Fragilicious]

Ok, so with almost no internet connection where I was on holiday, I have only created a new continent because my map was too small for a globe but nothing else has been done. I intend to throw myself into the project now.

Lots of things have been studied and decided but I'm looking for some more advice. Making a globe; my initial idea is to go to a hobby shop, buy a large paper ball (the ones used for planets and whatnot) and start drawing, but is there a program out there that will allow me to do it digitally? Preferably, a blank globe upon which I can place the existing continents, draw the tectonic plates, and then flatten out into an image I can work with?

:Edit: Done it with photoshop.

Thanks.