1. Name: SightSpeak
2. What it does: This script makes an NPC talk to the player as soon as he 
sees him. No triggers required.
3. Notes: My NPC's tag is Pathal, change it to whatever your NPC's tag is 
for you. Put this in the NPC's OnPerceive Event.
4. The Script itself

.nwscript 
void main()
{
string sTag = "Pathal";
object oNPC = GetObjectByTag("Pathal");
object oPC = GetLastPerceived();
if(GetIsPC(oPC) &&
GetLocalInt( oPC,"SR_Init" + GetTag(oNPC)) == FALSE &&
IsInConversation(oNPC) == FALSE)
{
AssignCommand(oPC, ClearAllActions());
AssignCommand(oNPC, ClearAllActions());
AssignCommand(oNPC, ActionMoveToObject(oPC));
AssignCommand(oNPC, ActionStartConversation(oPC));
}
}
./nwscript

Cyber_Bruno

P.S. it's on a trigger's OnEnter event.