Here are some Invader Zim sounds and songs.
Right click on the link and select "save target as" to download it. Or just click on it to listen to it without downloading it.

Aircraft.wav - This is where GIR comes to save Zim dressed up as a government agent.

GIR.wav - GIR as government man expresses his affection to a stranger.

GIR.wav - GIR greets a little one.

GIR.wav - An order from GIR.

GIR.wav - GIR mourns over the loss of his little friend.

GIR.wav - GIR walks along.

GIR.wav - How we all feel about Invader Zim.

GIR.wav - GIR likes many TV shows.

GIR.wav - GIR fooling around.

GIR.wav - GIR mourns over the loss of baked goods.

GIR.wav - GIR does not exactly know what "doomed" means.

GIR.wav - GIR claims that he saw a tamiasciurus hudsonicus.

GIR.wav - GIR tries to cheer Zim up.

GIR.wav - GIR wants to be a herpestes edwardsi.

Gaz.wav - Gaz gets a little mad.

Gaz.wav - Gaz looks for her brother.

Ms. Bitters.wav - Ms. Bitters tells her students to reach for the stars.

Zim.wav - Zim demands more of GIR's little friends.

Zim.wav - Zim breaks his spine.

GIR.wav - GIR "forgets" his precious chip.

GIR and Zim.wav - GIR and Zim laughing hysterically.

Entering Earth's Atmosphere.mp3 - This is when Zim and GIR enter Earth's atmosphere for the first time.

Theme Song.mp3 - The Invader Zim theme song.

In the Beginning.mp3 - The song at the beginning of the first episode.

Parents Waltz.mp3 - The music from when Zim was making his robot parents.

Bank Robber Chase.mp3 - This is from the episode where Zim is mistaken for a bank robber.

Battle Dib.mp3 - This is where Dib has to battle a strange creature so that he can see his Dad, Dr. Membrane.

Escape on the Pig.mp3 - This is where Zim and GIR escape from the alien lovers on a flying pig balloon.