This page will be a collection of links to aids, some documents, etc. of use to the amateur radio operator for handling message traffic.
Traffic Handler Training courtesy of the Texas Traffic Net — a super page that will walk the novice traffic handler through everything they need to know.
Some pieces from that site:
Handling Instructions (HX codes)
ARRL numbered radiograms (ARL codes) — includes both the emergency codes and routine codes
Other Aids
National Traffic System Methods and Practices Guidelines , especially the section on sending message on voice nets.
ARRL Radiogram — fillable on your computer
ARRL Radiogram — suitable for printing
Disaster Welfare Message — radiogram specifically intended for this type traffic (d/l from ARRL)