How can I help develop ngspice ?
Ngspice is an open project, there is no closed group of developers. Different "groups" gathered and dissolved in more than 5 years of development. To become an ngspice developer is very easy. There is no formal step to take for joining the development team. You have only to subscribe to the development mailing list and introduce yourself.
If you do not want to take an active role in ngspice development, you can always help becoming a beta tester. The quality of ngspice strongly depends on the number of tests we are able to run on each release.
A third way to help develop ngspice is in writing its documentation. Documentation for ngspice is not completed, needs proof reading and some updates.
Ngspice in an international project, so the "official" language used on the lists is english.
Developers mailing list
The developers mailing list is ngspice-devel. The list is an high volume mailing list and messages may be quite long (they may contain source code attachment). The level of discussion is technical. To join it point your browser to the list administrative interface.
Ngspice source code repository
Ngspice source code is stored in a git repository that is open to everyone for reading. Anyone can get the latest sources or browse repository content with a web browser. Details are explained in the git access page.
Sourceforge summary page
Sourceforge offers many services to help developers keeping up with the development activity. You can access all of them through the summary page.