See the NER site
http://www.porschenet.com/winter.html for one.
FYI, I use the Porsche battery maintainer, which plugs into the cigarette lighter socket. If you have a power outlet available where you store the car, this works great and saves you from tripping over the battery on the way to the washing machine all winter
.
I also do the yearly oil change just before storage - one "between exits" run on the highway and then straight under the cover it goes. I've received lots of cautions about leaving a significant amount of combustion by-products sitting in the engine all winter...
Fresh gas for a full tank and use gas conditioner (StaBil, etc.) at the last fill.
I've yet to try putting the moth balls on top of the engine to keep the mice from nibbling their seeds up there, but this may be the year!