CD Projekt RED has announced that REDkit, their official set of tools, is now available for public consumption. The tools allow amateur modders to try their hand at making the game better by creating new characters and quests for The Witcher 2.
Modders can also modify maps and terrain with the tool, using a unique SpeedTree system that allows for easier creation of group vegetation. A new wiki was released as well and it is encouraged that all prospective modders check it out prior to delving deeply into the tools. User-created mods can be uploaded to CD Projekt REDs website where those looking for a new experience can browse for new mods.
Mods are pretty sparse at the moment, with only a singular quest mod available for download. Despite being in alpha at the moment, the mod already boasts several hours of gameplay and dialogue for anyone who wants to give it a shot. I can imagine that modding community for this title to grow fairly rapidly due to the rabid fanbase that The Witcher series has.