FIRST OFF, YOU MUST HAVE FULL ACCESS TO A PC. IF YOU DO NOT HAVE FULL ACCESS TO A PC THEN DON'T EVEN BOTHER READING THIS POST. SORRY. OTHERS HAVE SAID HOW TO DUE THIS UPGRADE IN THE PAST, BUT NEVER INCLUDED THAT YOU MIGHT NEED ACCESS TO A PC.

If you own an older PowerMac G4(with a AGP slot) that doesn't have a Superdrive; but, you want a way to burn DVDs with iDVD and other programs, then I have a suggestion:

Pioneer DVR-105(OEM version)

They can be found through Pricewatch for under $150(shipping included) on various sites.
You can get the better versions, but the OEM version works just as good(get the Black Bezel model it is the lowest price)!

Here is what you need:
1. Full access to a PC(for the 1.33 firmware update)
2. PowerMac G4(AGP slot recommended) running OSX
3. Pioneer DVR-105 drive(OEM version recommended, because that is what I used)
4. Apple's iLife software

PC instructions:
1. Go to the Pioneer site and download two things: a)firmware checker for DVR-105 b)1.33 firmware update(SAVE THEM BOTH TO DESKTOP SO THEY WILL BE EASY TO FIND)
2. Install the Pioneer drive in the PC
3. Restart the PC and use the "firmware checker" 1.30 will work for Mac(at 2x DVD write speeds), but 1.33 is the lastest so if it is not 1.33...then update the firmware to 1.33 for full 4x write speeds on the Mac.
4. Once firmware is updated turn the PC off and remove the Pioneer drive for installation in the Mac

Mac instructions:
1. If you have iDVD on your system remove it before installing the Pioneer drive.
2. Install the Pioneer drive in the Mac and power it up
3. Go to "About This Mac" under the "Blue Apple menu"
4. Click "more info", followed by clicking "devices and volumes"
5. Under "BUS" you will see CD-RW/DVD-R click the down arrow
6. It will say Disk Buring Fully Supported.
7. Once the Pioneer drive is installed and you see that it is indeed fully supported, then load iLife's iDVD 3 on to your system. You will see that SUPERDRIVE is detected.

Now technically this isn't a Apple Superdrive, but it will do all the functions of one. Your machine will think it is one. If you follow the instructions correctly in getting the 1.33 firmware update you will be burning DVDs made with iDVD at 4x speed in no time for around or just under $200($150 for the drive & $49.99 for iLife).

Unfortunately, there is one known issue. Waking the Mac from sleep will now be a problem. It can take up to 2 minutes to wake up, or it just won't wake up at all...requiring a restart. Turn off sleep options under System Preferences. Other than that I have seen no other issues. The drive continues to work in OS 10.2.8 just as well as it did in OS 10.2.6.