GNUstep project, as many open-source software (OSS) is being developed by many developers from all around the world. The project uses various tools for supporting the development.
You can talk to some (not all use IRC) GNUstep developers on IRC:
Server: irc.gnustep.org or irc.gnu.org or irc.debian.org
Configure your IRC client and join the channel:
http://www.gmane.org carries the GNUstep mailinglists by NNTP