From where I can get DTK source.
You will need to go to the download area for the DTK: http://software.intel.com/en-us/articles/download-the-latest-version-of-manageability-developer-tool-kit
Gael is correct but this source code is limited to the Intel AMT DTK stack and Intel AMT Terminal. I will be making an update and adding more source code in the coming week to match the release to the new Intel AMT SDK. It should occur in about 3 weeks.
Ylian (Intel AMT Blog)