I never worry too much about distortions on flat maps. Technically they should be skewed the closer you get to the pole (ie lands get widened out so that when pinched they fit on a spherical globe). But on flat maps the lat/long lines run up and down, left and right so I just draw continents to a grid. It's all relative and informative, not technically precise. Maps meant to be wrapped around a sphere in a 3d program get the distortion and for that you could use Fractal Mapper 8 to get a base layout and general shape ideas.
In order to get your distortions correct, if that's what you want to do, then take a look at this thread as RobA explains how to wrap a flat map around a sphere in Google Earth.