This document provides detailed information on the different messages that are within Day of Defeat
Written by Geesu (Pimp Daddy)
Messages ID Args Argument Order Description of Arguments Notes
AmmoPickup
AmmoShort
AmmoX 87 2 byte, byte
BloodPuff 3 coord, coord, coord 1: X, 2: Y, 3: Z Coordinates of where to create a BloodPuff
CameraView
CancelProg
CapMsg 3 byte, string, byte
ClanTimer
ClCorpse 10 string, coord, coord, coord, angle, angle, angle, byte, short, byte
ClientAreas 3 byte, byte, string 1: Unknown, 2: Unknown, 3: Sprite Path This message is called when an icon is shown on your screen, like when you walk over an objective.  An examples of the 3rd argument would be: sprites/mapsprites/caparea.spr. The 2nd argument is usually -1.
CurMarker
CurWeapon 3 byte, byte, byte
DeathMsg 3 byte, byte, byte
Frags 2 byte, short
GameRules 2 byte, byte
HandSignal
Health 1 byte
HideWeapon 1 byte, byte
HLTV 2 byte, byte
HudText 2 string, byte 1: Text to send, 2: Flag If the flag is 1 then the message will be shown, if it's 0 it will not be shown.  ANY Text can be sent through this message (unlike the CS/CZ version)
InitHUD
InitObj 27 short, byte, byte, byte, byte, byte, byte, coord, coord, short, byte, byte, byte, byte, byte, byte, coord, coord, coord, byte, byte, byte, byte, byte, byte, coord, coord
MapMarker
MOTD
Object
ObjScore
PClass 2 byte, byte
PlayersIn 4 byte, byte, byte, byte
ProgUpdate
PShoot
PStatus 2 byte, byte
PTeam 2 byte, byte
ReloadDone
ReqState
ResetHUD
ResetSens 0 NO ARGUMENTS
RoundState 1 byte 1: Flag Flag values: 3 = Allies Win, 4 = Axis Win, 5 = Draw
SayText 2 byte, string 1: Message Destination, 2: Message
Scope 1 byte
ScoreInfo 7 byte, byte, byte, byte, byte, byte, byte
ScoreInfoLong
ScoreShort 5 byte, short, short, short, byte
ScreenFade 7 short, short, short, byte, byte, byte, byte 1: Duration, 2: Hold Time, 3: Fade Type, 4: Red, 5: Green, 6: Blue, 7: Alpha
ScreenShake 3 short, short, short 1: Amount, 2: Duration, 3: Frequency
ServerName
SetFOV
SetObj 3 byte, byte, byte
ShowMenu
Spectator 2 byte, byte
StartProg 3 byte, byte, short
StartProgF
StatusValue 1 byte 1: Amount This one byte contains the health of the player that is being spectated
TeamScore 2 byte, short 1: Team ID, 2: Score
TextMsg 
TimeLeft 1 short 1: Timeleft
TimerStatus
UseSound
VGUIMenu
VoiceMask long, long
WaveStatus 1 byte
WaveTime 1 char
WeaponList
WeapPickup
Weather
YouDied
Other valuable DOD Coding Information Regarding Messages:
Trying to determine who a certain player is spectating?
Register this: register_event("StatusValue","on_StatusValue","b")
And here is the on_StatusValue function:
public on_StatusValue(id){
     new targetid = entity_get_int(id, EV_INT_iuser2)
     if( targetid == 0 )
          return PLUGIN_CONTINUE
     // Do Stuff here
     return PLUGIN_CONTINUE
}
Note: Even though StatusIcon isn't registered as a message, it is possible to register this message (I lost the code to do this, but I have done it)