It took a bit of hunting (everyone seems to be linking to the Levitsky one in preference to anything else, and it _is_ the best thing out there to walk people who don't know Blender through out there), but I found a pre mapped sphere to download. After you've messed up your sphere, you just go baking when in UV Select mode (you may need to add a new image...I seem really good at managing to lose my images loaded. That's at least reasonably straightforward). Assuming you don't mind doing a bit of work _un_ sculpting, the Levitsky tutorial has the file at the bottom as well, so you can start with almost-a-cylinder that's pre-mapped. I think I found a clean cylinder base somewhere, but arsed if I can find where now.
This should get your map oriented the right way (and, one hopes, not inside out, since they changed the orientation necessary midway through development) so sides are sides and tops are tops, as well as skipping the beastly coord stage, which mostly just sucks with the power of a thousand suns.
Note: sculpt maps are most efficient (and, generally, successful) when the rainbow image map is 64x64, due to LOD and ceilings on vertices.