Thanks to all for the suggestions and recipes. I will check the websites suggested and the liquor stores here in Denver.
Branbal77: please post the recipe for all of us when you get a chance. Thank you!

Just remember what Ira said. If it is not made from the lemons from the Amalfi Coast it really will not be the same. So much easier and much better to just buy the Limoncello made in Italy.

Thank you LoveItaly, I also prefer/plan to buy authentic Limoncello from the Amalfi Coast. Like Ira said, the lemons from there are truly special and unique. I am just curious about the way it is made which is why I'm interested in the recipes.

This is the recipe here. I do not know about differences in lemons except that the lemons here in Sardegna are huge, about three times the size of those in the states.
The alcohol used is pure alcohol. Italians do not use vodka. I would assume, since I have not made it in the states, that you could go to the local liqour store and ask for pure alcohol. I use 96 proof. Limoncello does not require much just some TLC!
It is really good to substitute madarins, 12-14, for the lemons and, being in the states, I would up the lemons to at least 10!

Peel 8 lemons and put the peeling in a glass jar and add 1 liter of alcohol
(pure not vodka or rum etc) and leave it for 7 days. After the 7 days, remove the peelings. In a pot pour 1& 1/2 liters of water and 2 pounds of sugar and heat. Stir just long enough to dissolve the sugar. Let cool to
room temperature. Then, mix the sugared water and the alcohol/lemon mixture together and let it set for 2 days. This will make approximatley 3 liters of limoncello/ I keep mine in the freezer. You will need bottle with screw tops or something similiar to store it. The freezer will make it nice and cold..yummy!!!