Hi Susan,
We use butternut squash quite often and don't have a problem preparing it. I cut the small end off, and then cut off the large bulb end just as it starts to curve out, this usually is just where the seeds start. You can then cut the peel off the large straight section with a big knife by standing it on one of the flat ends and slicing down, that section then cuts into cubes quite easily.
I then scoop the seeds out with an ice cream scoop , cut the bulb into 4 and these pieces can then be peeled quite easily with a sharp knife and cubed again.
We use it in stews and soups and also in a tomato, red pepper and squash puree with prawns.
I've never seen it sold ready prepared, but maybe others know different.