Can a new rear panel & 80G battery fix a 2006 30G?

Karen, I believe your "Classic" is actually a 5th gen iPod video. If it is, then the 80GB will fit if you also replace the back. The only issue with that is that you will not see a big increase in battery life. you will also have to be careful that the hard drive will not be dislodged since there will be more room. You will need to add some foam to decrease that space. Once you clarify which iPod you have we can show you the right guides. It is not difficult at all. Here is the guide for the 5th gen Video and the battery is available right here as well as many other places. Hope this helps, good luck.