All code (excluding the BuildCraft API, which is covered by the BuildCraft license) is licensed under the WTFPL (Do What the Fuck You Want to Public License http://www.wtfpl.net/). Do what you want with it, as long as you smile while doing so. While it is not a requirement, it would be nice to know if it is being used and how, so send me hello to crazypants.mc at gmail.com.
###Sound Credits
Most sound attributed under Creative Commons Attribution 3.0 Unported (CC BY 3.0)
Credits: