Help! Need help with preflight package script

Question

I am trying to write a package with Iceberg to push Office 2004 to 250 Macs. I need a preflight script with a condition that will stop my script if /Applications/Microsoft Office 2004 exists OR if OFFICE 2004 exists. Don't know if searching on the folder name is the best or if there is better way
If it doesn't exist I want it to continue with with placing Office 2004 in the /Applications folder.
I don't know how to do conditions (If, then, end)
PREFLIGHT SCRIPT
IF /Applications/Microsoft Office 2004 folder exist = STOP
IF /Applications/Microsoft Office 2004 folder doesn't exist continue with laying down files/folder in the package.
LAYDOWN FILES
LAY DOWN FILES IN ICEBERG FILE SECTION OF THE PACKAGE
POSTFLIGHT SCRIPT
#!/bin/sh
#Change to root directory
cd /
# Move Microsoft Office X folder to Messages Received folder
mv /Applications/Microsoft\ Office\ X /Messages\ Received
#Open Office 2004 Installer
open /Applications/Utilities/Installers/Office2004Installer
ALL Mac OS X (10.4.6)
ALL Mac OS X (10.4.6)
ALL   Mac OS X (10.4.6)  

Answer 1

A simple condition (not using iceberg) would be:
#!/bin/sh
if [ -e "/Applications/Microsoft Office 2004.app" ]
then
echo "Microsoft Office 2004 exists, aborting installation"
exit 1
fi
open -a "/Applications/Utilities/Installers/Office2004Installer"
If Microsoft Office 2004 is installed then the script will exit with a message. If Microsoft Office 2004 is not there then the last line will be executed and the installer will open.
PowerBook G4   Mac OS X (10.4.8)   MacBook Pro