Chats and Forums

CoolRunning
Offers sections pertaining to different ways of training for different levels of runners and special interest groups.
http://www.coolrunning.com/cgi-bin/ubb/Ultimate.cgi

Hillrunner.com
A running forum and regular scheduled chats 8:00 ET Mondays and Wednesdays.
http://www.hillrunner.com

Marathon Guide
Many categories for discussions related to marathon running.
http://www.marathonguide.com/bulletinboards/index.cfm

Myjjk
Forum about running and track and field. Post questions and share advice.
http://www.myjjk.com/

Run-Down
Popular forums from a website that is centralized around its database of links to other running websites. You have to become a member if you want to post anything.
http://run-down.com/forum/

RunnersWeb.com
These forums branch out of the world of running a little and also cover triathlon and multi-sport activities.
http://www.runnersweb.com/running/forum.html