If you look at the official Unreal Tournament 2003 site under the F.A.O section at the bottom of the page you're going to see this:

What game modes will there be?

Deathmatch
Team Deathmatch
Capture the Flag
Domination 2.0
Bombing Run

Want to know what the Maps are called in the game modes Capture the flag, Death match and Domination? Then hit Read More. Capture the Flag:

Chrome
Maul
Kretzig
Lethargic
Lava Giant2
Lost Faith

Death match:

Tokara Forest
Asbestos
Vidona
Compressed
Antalus
Insidious
Flux2
Inferno
Vidona
Leviathan
Gestalt

Domination:

Sepkku Gorge
Core
Temple Anubis
Outrigger
Ixcorra

Big thanks to Brownie! :D