Instructions
Download and install a DVD conversion application. Handbrake is a popular, free application; see "Resources" for additional applications.
Insert the DVD into your computer's DVD-ROM and open the conversion application.
Select the inserted DVD as the "Source." Adjust the necessary settings (file size, format, quality) and select a folder in which to save the output. For the best quality and compatibility, use the MPEG-4 format, though the Xbox can read DivX-encoded videos as well. Click "Start" to begin converting the DVD to a digital video file. It is important to refer to the application's user guide for any specific settings or instructions. It may take a few hours to completely rip the DVD.
Insert a USB flash drive into your computer's USB port. Drag the resulting digital video file from their folder to the USB drive. Disconnect the drive once the transfer is complete.
Plug the USB flash drive into the USB port on the back of the Xbox 360 and power on the system.
Navigate to "Video Library," then select "Portable Device." Select the inserted USB drive, navigate to the video file and select it to begin transferring and playing the DVD movie on your Xbox 360.