First, the HTC One X gets root before launch, and now the HTC One S follows suit using MoDaCo’s Superboot. Superboot is a script that you run on your computer when the device is connected via the USB cable that pushes all the necessary files to your phone to attain root.
The one caveat is that for this method to work, the phone needs to have S-OFF (which means the NAND portion of the device is writable) or needs an unlocked bootloader. As of this moment, none of the HTC One series of phones are available in the HTC bootloader unlock tool, but we’re hoping for that to change soon after launch. Once the phone’s bootloader is unlocked, just run Superboot and you’ll be riding the root train!