There are a number of other forums:
The official JET forum: JET Programme :: Index
The old forum was a bit klunky but the new one is much cleaner and friendlier
Big Daikon: BigDaikon
You have to be fairly thick skinned here. Not as civilised as ITIL
Virtual JET Workshop: The JET-Programme Forum - A Virtual JET Workshop - Index
This one is new and broader based. A good concept but doesn't seem to have taken off yet.
Gaijin Pot: Japan Forums
Some people post here though it is not JET focused.
All of the above have different characters so just surf around and choose the one(s) that suit you best.