This has been posted by Lance Botelle on Bioware forums.

This fires the Atari Logo movie file (WHICH COMES WITH NWN2) ... simply replace "AtariLogo" with the BIK file you need to play, and make this a unique XML file.

LBMovie_AtariLogo.xml

<?xml version="1.0" encoding="utf-8"?>

<!-- Main Menu definition -->
<UIScene name="SCREEN_MOVIE" x=0 y=0 idleexpiretime="0.1"  priority="SCENE_INGAME" fullscreen=true scriptloadable=true  backoutkey=true
	OnBackout=UIObject_MISC_ExecuteServerScript("gui_lb_movies")
	OnAdd0=UIScene_Misc_SetPauseState("true")
	OnAdd1=UIButton_Input_ShowMovie("AtariLogo") />

<!-- Define the MOVIE background -->
<UIIcon name="MOVIE_ALPHA" img="solid_black_fill.tga" x=0 y=0 width=PARENT_WIDTH height=PARENT_HEIGHT scalewithscene=true
	OnMouseEnter=UIObject_MISC_ExecuteServerScript("gui_lb_movies")/>

gui_lb_movies

void CloseMovieScreen()
{
	object oPC = GetFirstPC();

	while(oPC != OBJECT_INVALID)
	{
		CloseGUIScreen(oPC, "SCREEN_MOVIE");

		oPC = GetNextPC();
	}
}

void main()
{
	// Set to TRUE for single player module
	SetPause(FALSE);
	DelayCommand(0.01, CloseMovieScreen());
}

onused_openmovie

// OnUsed to open the Movie GUI
void main()
{
	object oPlayer = GetLastUsedBy();

	if(GetName(OBJECT_SELF) == "MOVIE")
	{
		// the movie name is in a local variable
		string sMovie = GetLocalString(OBJECT_SELF, "MOVIE");

		// open the GUI associated with the movie
		DisplayGuiScreen(oPlayer, "SCREEN_MOVIE", TRUE, "LBMovie_" + sMovie + ".xml");

		SendMessageToPC(oPlayer, "<<< MOVIE PLAYING >>>");
	}
}