UK based Fencing Forum 
http://fencingforum.com/forum

Plenty of info on the sport, used by lots of fencers, coaches, and others - all abilities catered for.  Sponsored and provided by Leon Paul Equipment, but most contributors are not connected to them.

USA based fencing forum
http://www.fencing.net

US-centric forum, many interesting articles. 

fencing.net's YouTube channel
http://www.youtube.com/user/fencingnet

Lots of good fencing clips of all types.  YouTube also has a load of coaching info as well.