Download the Demo
The free demo is 97MB and is available from a variety of sources, however, the best place to check for working mirrors is the Official Unreal Tournament 2003 Site under the Downloads section. The site also has more details about the upcoming full release of UT 2003 and a useful FAQ.
Note: A new patch has been released for the demo! It's 3MB and can be downloaded from the link above. It solves several bugs and resolves problems with 3dfx graphics cards.
Go through and adjust all the settings to taste, getting a good balance between visual quality and performance on your machine. I have some recommendations for the major settings:
Video: To avoid problems, make sure you select Full Screen and set the Color Depth to the same as your desktop (32-bit recommended for both). Also set Contrast to 1.00 for sharpest image.
Details: The four settings at the top of this screen have the biggest impact on framerates, especially Texture Detail and World Detail.
Audio: Under Audio mode, make sure you use the Hardware 3D if available (+EAX if you have supported card) to improve sound quality dramatically. This may decrease graphics performance slightly however.
Player: The maximum number of characters for your player name is limited on this screen. See the Advanced Tweaks section below for a workaround.
Make sure you go through all the settings and customize them first. Once you've done this, we can move to the next phase of tweaking.