Flux is worked on full-time by Facebook's product infrastructure user interface engineering teams. They're often around and available for questions.
Many members of the community use Stack Overflow to ask questions. Read through the existing questions tagged with reactjs or ask your own!
The reactjs Google Group is also a good place to ask questions and find answers.
Many developers and users idle on Freenode.net's IRC network in #reactjs on freenode.
#fluxjs hash tag on Twitter is used to keep up with the latest Flux news.