If you cannot get your Mac OS X Install DVD to work (I cannot get my drive to read ANY dvd at the moment!) or if you simply cannot find it and you need to launch bootcamp setup on windows 7 after installing it on your mac, then this site should help:
Control click Boot Camp Assistant > Show Package Contents
Open Contents > Resources
Copy contents of Diskimage to either a USB Key or a cd.
Job done. That's the same install package that is on the Leopard disk. Just un setup.exe and away you go.
Hope this helps.
The easiest way is to download the drivers directly from Apple's website
Look for "Software Update" (last time i check is on the right hand side) and download the drivers for the version of Windows you're running.
It's an .exe file so you can save it in your USB key etc and simply run it under windows.