There was a soundtrack for the movie released it contains the following tracks:
1) My Little Pony Opening Chorus
2) We're Witches
3) I'll Go It Alone
4) I'll Do the Dirty Work
5) Nothing Can Stop The Smooze
6) There's Always Another Rainbow
7) Home
8) What Good Could Wishing Do?
9) My Little Pony Ending Chorus
Due to it being the 80s of course! It only ever came out on LP and cassette.
There is no other formal release of MLP music other than the occasional cassette but they tended to be more story driven with music also featuring.
I have quite a few as mp3 files if you would like - just pm me and I can email them to you - including the ever awesome Call upon the Sea Ponies.