In a new post to his blog, Pierre-Alain Joye has a suggestion for mailing list members (and really anyone else involved with the community) for reading materials - a chapter from "Producing Open Source Software".
A must read about OSS is the "Producing Open Source Software" written By Karl Fogel. One chapter covers nearly all problems that php Internals is experiencing.
No need to say that these rules should apply to IRC as well. You may think while reading the mailing lists that a certain level has been reached, what happens on IRC is even worst. Another chapter can be very interesting: Social and Political Infrastructure (and related). Mixing paid developers, volunteers or ambitious developers (as in need of an ego or career booster) is not an easy thing, but it should be possible (dreaming?).
Among the topics discussed in the chapter, Pierre mentions two - "nip rudeness in the bud" to keep things more civil and from escalating and to avoid private discussions about a project that everyone should be involved with.