The following are online communities that can be useful resouces for video workflows.
Creative Cow - A great number of forums that are moderated by video experts.
DV Info Net - Another great site with tons of forums about video software/hardware with users helping each other and giving advice on production and post-production workflows.
LAFCPUG - The Los Angeles Final Cut Pro User Group - a great place for information for people who use Final Cut Pro.
Avid Forums - Avid's company run user forums .
Adobe Forums - Adobe's company run user forums.