Fix it with an iFixIt SATA optical Bay Enclosure
My granddaughter's 2006 Mac Mini would not support her iPad Mini in iTunes and she ran out of space on the original 80GB drive. Also, the computer had become slow. Answer: An iFixIt optical bay drive enclosure. I put an SSD where the original drive was and a 500GB drive into the enclosure - brilliant, worked like a charm! I was concerned about PATA speeds but it's not really a problem.
It went extremely well. The iFixIt tutorials are amazing. It's the first place I look for tutorials. So clear, so well done with very high quality images. I had no problem changing the processor, the memory, the hard drive or installing the enclosure. All thanks to iFixIt. Afterwards the machine Mac Mini booted up in 15 seconds and apps come up immediately. With plenty of storage and a Lion OS, my granddaughter will be really pleased. It took minutes to boot up before.
Be patient when inserting the enclosure. There is a small circuit board at one end that presents a challenge because of the tight fit. If you feel like you are forcing things, stop and try again. The plastic filler is too loose so I ended up throwing it away. You don't really need it anyway after you insert the two screws into the HD from below. The filler just keeps falling out. Also, the PATA connection is a bit finniky to get tight but once in, it's there to stay. A great enhancement for any Mini.