John Williams
Modern
allegretto
depends
For the Star Wars films, John Williams is the sole composer. Kevin Kiner has done the composing for the Star Wars: The Clone Wars animated series, but the themes follow the consistency of the John Williams scoring.
its The Imperial March--Darth Vader's theme
It's officially called "Star Wars Main Title."
the theme song
The Sith Theme Song
you buy it
Goldentusk's Star Wars Theme Song - 2009 was released on: USA: 5 January 2009 (internet)
Modern
One can sing the theme song for Star Wars anywhere they really want to. One could sing it in the shower, while cooking dinner, or with a group of friends at a Star Wars convention.
He did not write the theme song, but he did do an excellent cover of it.
No. No it hasn't.
allegretto
depends
John Williams composed the original Star Wars theme & music for the movies & as of this answer [June 2017] he is very much alive & still composing.