I've been looking everywhere for the name of the song that plays during the march on the Jedi temple in Revenge of the Sith:
I can't find it on the official soundtrack and Shazam can't identify it.
Hopefully someone knows, thanks!
Within the context of Episode 3, the song is called "Order 66 and the Jedi Temple". It is not included on the official soundtrack/score as it was mostly a re-use of the song from Attack of the Clones as Jason Baker has indentified.
According to Wookieepedia, the song is originally from the Attack of the Clones sountrack1; the title is "The Arena" (emphasis mind):
In Attack of the Clones, the theme is used only during the planned executions of Anakin Skywalker, Obi-Wan Kenobi, and Padmé Amidala in the Petranaki arena on the planet Geonosis, though here the majority of the theme is cut out, except for the moments scoring Poggle the Lesser announcing the start of the executions up until Skywalker tames the reek. It is also used in one of the DVD's main menus. The theme is used again in Star Wars Episode III: Revenge of the Sith to introduce the planet Kashyyyk prior to the battle there, and again when Darth Vader attacks the Jedi Temple on Coruscant during Operation: Knightfall.
Here it is on YouTube:
1 On the commercially-released soundtrack, this song is listed as "Love Pledge and The Arena"; it shares double-billing with the song that plays during the scene between Padme and Anakin before the arena scene in Attack of the Clones
Love Pledge and the Arena, Attack of the Clones.
The theme starts at 2:30 into the song.
The song is called "March at the Jedi Temple".