I dont know of any event triggered when your send starts sending so, i wrote something on a timer....

ANYONE KNOW OF AN EVENT TO HOOK IN ON?

The 61 and 60 in the below alias is for a 60 second monitoring, if you want to increase it then increment that number up as needed.

Code:
;
;usage $start.watch.for.dcc.send(nick,filename,channel,message)
;usage !.echo -q $start.watch.for.dcc.send(nick,filename,channel,message)
;usage /start.watch.for.dcc.send nick filename channel message [ this option limited to filename having no spaces ]
; 
alias start.watch.for.dcc.send {
  var %timername = $+(WFDS.,$ticks,.,$rand(100001,199999))
  set -u61 % $+ [ %timername ] $+ .nick $1
  set -u61 % $+ [ %timername ] $+ .file $2
  set -u61 % $+ [ %timername ] $+ .chan $3
  set -u61 % $+ [ %timername ] $+ .mess $4-
  .timer $+ %timername 60 1 watch.for.dcc.send %timername
}
;
alias -l watch.for.dcc.send {
  var %nick = [ % $+ [ $1 $+ .nick ] ]
  var %file = [ % $+ [ $1 $+ .file ] ]
  var %i = $send(%nick,0)
  while (%i) {
    if (($send(%nick,%i).file == %file) && ($send(%nick,%i).status == active)) {
      var %chan = [ % $+ [ $1 $+ .chan ] ]
      var %mess = [ % $+ [ $1 $+ .mess ] ]
      msg %chan %mess
      .timer $+ $1 off
      unset % $+ $1 $+ .*
      halt
    }
    dec %i
  }
}


That above is designed to be a routine u call when your doing a dcc send, it doesnt run on its own.

Directly precedding the dcc send (or directly following it) you need to do
$start.watch.for.dcc.send(nick,filename,channel,message)
* nick is the nick your sending the file to
* filename is the filename
* channel is the channel gfor your message (you can use a nick if u want)
* message is the message

so assuming your doing

/dcc send %nick %filename

then add to it to make....

/dcc send %nick %filename
$start.watch.for.dcc.send(%nick,%filename,#wombatworld,Master Wombat $me has started to send %filename to %nick so says the scrolls of wombatness)

above is a channel message or below is a private message

/dcc send %nick %filename
$start.watch.for.dcc.send(%nick,%filename,%nick,In case your completely blind in which case you wont see this anyway I am sedning you the file %filename now!)



*** limitations you cant have a comma in the message, u need to make it $chr(44) becuase the comma well seperate the parameters
*** The reason I dont call the alias using /start.watch.for.dcc.send nick filename channel message is becuase the filename MAY have spaces in it, if it doesnt then you can use /start.watch.for.dcc.send