So the group is not that active (avg 4-5 posts per day) and there's so as much resources dedicated to it as a newbie might have hoped- here's what this newbie has found helpful:
for creating and configuring the plugin , the tutorial on the main plugin developer's page.
for learning the Psi, which basically has no javadoc- the MetricsReloaded download has a lot of code that makes OK examples. The other Open Source plugins are either so highly specialized it's hard for them to serve as general how-tos or they're standalone programs that just interface with IntelliJ without really using the API all that deeply.
Hopefully in the future we will see more resources available and a more active community with more senior members able to answer questions.
I personally think growing the pool of Psi-knowers is in all our best interests, even if it means repeating the same info. a few times to different people since the more people who understand it, the more of the burden that growing number of people people can take off dedicated IntelliJ developers who I am sure would rather be coding something interesting than answering newbie questions over and over again.
Sometimes communities get into knowledge hording if they think their perceived competition could be helped by offering info. I don't think that' s happening here, but it's always true that the more value all plug-in writers add to IntelliJ, the more attractive IntelliJ is to consumers, the more copies IntelliJ sells, the more copies of all plugins sell also. The best way to grow your business is to make the ocean of IntelliJ users larger by adding value and by helping others to add value.