Please find the sources for each subproject at https://github.com/GPGTools/
For further details please visit http://gpgtools.org
To create your own installers
bash -c "$(curl -fsSkL raw.github.com/GPGTools/GPGTools/master/build.sh)"
Installer that contains everything needed for Encryption on OS X (GPGMail, GPG Keychain Access, GPGServices and MacGPG2)