I'm working off an older system, 10.5.8 and want to upgrade,but it won't let me without getting the 10.6.3 disc upgrade,now the problem with that is the internal cd drive won't work anymore and has a disc jammed in it,so I purchased the external USB SuperDrive, when I plugged it in the computer didn't recognise it, this Is really frustrating because I paid $100 for it and at the moment we can't access iTunes or even upgrade that for our iPhones or iPads,is there a way I can get the computer to recognise the USB drive? So I can do the upgrade.
It is possible to do it but it is not 100 guarantied. In the future please pay attention to the hardware requirements (Macs don't like hacks!).
The exact information is here: http://www.hardturm.ch/luz/2011/10/how-to-make-the-macbook-air-superdrive-work-with-any-mac/
You need to modify a system preference list which is mostly harmless but the annoying bit will be when you do any sort of software upgrade it could be "broken", meaning set back to factory settings.
If the stuck disc is spinning at all and just won't eject, there is a chance to get it out. This link has some options to try.
The one with the playing card worked for me.
Regarding the external SuperDrive not working on your Mac...just ran into this myself while at a Genius Bar appointment—in typical Apple fashion, the USB SuperDrive will only work w/ Macs that have no built-in SuperDrive (which is why the list of supported hardware shows only those Macs that don't have one built in). Though I was unaware of the loophole Andrew U mentioned and will be checking that out shortly.
Anyway...literally every time I've had a to deal w/ a CD/DVD stuck in a Mac optical drive the standard (though little known) trick has always worked: reboot the machine and as soon as the screen comes on (before the chime) press and hold the mouse (or trackpad) button, and only release either when the disc has ejected or the computer has totally booted up and there's still no disc (if the latter then it's good and stuck and I'd suggest going to an Apple Store for some Genius Bar help). It's also important to note that this will not work w/ mini discs, which should just never be put into a Mac's optical drive.
Another option (for installing the OS upgrade, not for getting the disc out), if you have access to another, functioning Mac, would be to use Disk Utility to make a disk image of the installer and save it to a flash drive or external disk that you can boot to and install (or maybe install from the Finder, but it's been a long time since 10.6 and I can't remember what would and wouldn't work back then).