You get it on the website. If it helps, here's the full license agreement:
Quote: "Newton Game Dynamics SDK License Version 1.52
Copyright 2003-2006 Newton Game Dynamics. All rights reserved.
LIMITED WARRANTY
This software is provided "as-is", without any express or implied warranty.
In no event shall the author be held liable for any damages arising from the use of this software.
This is a contract. By accepting the Newton Game Dynamics SDK (the SOFTWARE), you (either an individual or a single entity, the LICENSEE) accept the terms and conditions of this licensing agreement.
If the LICENSEE does not accept the terms and conditions, then LICENSEE must not accept the SOFTWARE.
If at a later time the LICENSEE decides not to continue licensing the SOFTWARE under these terms and conditions, then the LICENSEE must delete permanently all files constituting the SOFTWARE.
LICENSE AGREEMENT
Newton Game Dynamics Limited grants to the LICENSEE and the LICENSEE hereby accepts a perpetual nontransferable and nonexclusive license to use and distribute the SOFTWARE, for any purpose. In addition, the following conditions apply:
1) The LICENSEE may not use the SOFTWARE to reverse engineer the computer algorithm used by the SOFTWARE.
2) The origin of the SOFTWARE must not be misrepresented; If the LICENSEE uses the SOFTWARE to distribute a product, the LICENSEE must not claim that He or She wrote the original SOFTWARE.
3) The LICENSEE agrees to credit the use of the Newton Game Dynamics in any program information, including splash screens, "About" dialogs, program notes or instructions and shrink-wrapped packaging.
4) The LICENSEE may not redistribute the SOFTWARE, except as part of a compiled software program that is not itself a physics library.
5) The LICENSEE agrees to notify www.newtondynamics.com of any products, commercial, shareware or free that incorporate the Newton Game Dynamics technology.
Julio Jerez and Alain Suero
http://www.newtondynamics.com"
Coming soon...