A list of frequently asked questions (and their answers) is available here: Frequently Asked Questions
Training options are now available: training
Checkout our Discourse at https://forum.suricata.io/ (Trial)
Several users and developers mailinglists are available. You can subscribe at lists.openinfosecfoundation.org/mailman/listinfo
Tracking bugs, feature request and support requests is done on our redmine.openinfosecfoundation.org
We have an IRC channel on freenode.net, join #suricata.
Most of our development revolves around our redmine site: redmine.openinfosecfoundation.org