Although CD Projekt is releasing The Witcher 2: Assassins of Kings via GOG.com without the encumbrance of any DRM, all other versions of the game will apparently include the rather controversial SecuROM system. DUN DUN DUN, etc.
According to the developer, however, this is only to ensure that the game is not leaked ahead of its 17 June launch date.
The game will use a once-off online authentication login, and not require additional connectivity thereafter. The DRM also allows an unlimited number of installations on an unlimited number of PCs, and lets up to five people play the same copy at one time.
The Witcher 2 also includes an optional registration to receive notification of updates, as well as access to future free DLC releases.
As previously announced, of course, the version launched over GOG.com will not include DRM of any sort, and instead include a bunch of free stuff. Check out the preorder page for more info.