This is one of the most famous themes in classical music. The whole Symphony and particularly the 4th movement has been an enormous influence on later composers including Brahms and Mahler to name only two. Beethoven's 9th was the first significant "Choral Symphony" so called because the 4th movement includes soloists and a choir singing this theme and variations on it to the words of a poem written by Friedrich Schiller. This arrangement is for Piano Solo and we also have versions for many other instruments with piano accompaniment.
The theme has been adopted as the Anthem of the European Union (see our article on National Anthems), and it is also used as a Church Hymn with the words "Fill your hearts with joy and gladness". This melody and other parts of Beethoven's 9th Symphony were featured in the soundtrack of the film "A Clockwork Orange" in versions created on Moog synthesisers by Wendy Carlos. There is more information about such electronic instruments in our article about Electronic Music.