Music Composers Unite!
Absolutely necessary. There are currency and they are how you will get paid and track what is owed to you. Apart from the composer team and music editor, they are used by the music supervisor, the broadcast and distribution people, and ultimately the PRO's (ASCAP etc)... and the latter pay you based on what the cuesheet contains.
Even though they are a pain in the rear to do, it's worth becoming good at it. Know the difference between Background Vocal and Backgound Instrumental etc (the former pays 4 times as much by the way, which is which we composers are always sticking vocals on everything :) , and all the other specifics. Use a standardized format or you'll end up being asked to redo it or fit it into some TV station's format down the line.
OK. There you have it!
Is this it?
Here is an example of a basic cuesheet.