Splash.exe - small (3.5k), simple (one file) program that lets you throw 
up a splash screen in NSIS installers.

--- UPDATED in 1.50 - will break old scripts ---

To use:

Create a .BMP file of your splash screen.
(optional) Create a .WAV file to play while your splash screen shows.

Add the following lines to your .NSI file:

Function .onInit
  SetOutPath $TEMP
  File /oname=spltmp.bmp "my_splash.bmp"

; optional
; File /oname=spltmp.wav "my_splashshit.wav"

  File /oname=spltmp.exe "C:\program files\nsis\splash.exe"
  ExecWait '"$TEMP\spltmp.exe" 1000 $HWNDPARENT $TEMP\spltmp'
  Delete $TEMP\spltmp.exe
  Delete $TEMP\spltmp.bmp
;  Delete $TEMP\spltmp.wav
FunctionEnd

Note that the first parameter to splash.exe is the length to show the
screen for (in milliseconds), the second is the parent window (in decimal), 
and the last is the splash bitmap filename (without the .bmp). The BMP file
used will be this parameter.bmp, and the wave file used (if present) will be 
this parameter.wav.

(If you already have an .onInit function, put that in it)

Note: the return value of splash.exe is 1 if the user closed the splash 
screen early (you can check it using ClearErrors/IfErrors)

-Justin