I was given Adobe PhotoShop Elements 8 for Mac as a gift, however it requires an Intel-based Mac. I have a 5 year old iMac G5. Is there a version of Photoshop Elements available for my computer?

I think that AMD has dual core cpu's processors comparable to Intel but I am not a Mac user. I would think with 100% certainty that your computer must have the required operating system, Mac OS X v10.4.11 through 10.5.8 or Mac OS X v10.6. If you iMac does not have this os or the dual core processor, then you are out of luck.

It looks like PSE 6 will definitely run on a PPC, but I haven't found any info on PSE 7.