Update on 4-12-2011: Since creating this page I have learned from others on the forum and from my personal experiences that goose eggs do NOT need higher humidity during incubation. 45-55% humidity is better for them as it makes the air cell bigger giving them much more 'room' to breathe when they pip internally. To raise the humidity during hatch I just put a warm, wet, washcloth inside the hatcher.
I have also learned from experience that misting and cooling is not necessary. While it doesn't harm the eggs, it is not something to fret over.

Hey all! I have seen many posts regarding how to hatch goose eggs. I am on my very first goose egg hatch, and I have 2 eggs (from 2 total shipped eggs...thanks vicki 2x2!!) that have pipped the air cell!! Yay me!
Winter of '08/'09 I had been sent some eggs that were thought to be goose eggs, so I asked the experts here on BYC (mainly Miss Prissy) the best ways to hatch goose eggs. Here is what I came up with.
Most goose eggs take from 28 to 32 days to hatch. However, it is not uncommon for them to hatch anywhere from day 26 to day 35.

Goose eggs take the same temperature as chickens---99.5 forced air and 101.5 still air.
They also need a much higher humidity--at least 65% from days 1-26, then 85% or more until they hatch.

Cool the eggs for 15 minutes a day after day 4. Cooling eggs can be anything from removing them from the incubator as in a cabinet incubator; or simply removing the top of the incubator as in a styrofoam incubator.
You will also need to mist the eggs during the cool down with warm water until you see the first pip. Many people keep a small spray bottle of water inside the incubator. This will keep the water the same temperature as the eggs, as well as help regulate the temperature of your incubator.
Unless you have a cabinet incubator, hand turning is best. The GQF company that makes the hovabator also sells a goose egg turner, which you can order online. This will not work in a Little Giant incubator, as the top of the LG is not as high as the hovabator.
Make sure to wash your hands very well before handling the eggs! Goose eggs are very hard to hatch, which is why many of them are so expensive. You wouldn't want something as silly as contamination from you to be the reason your eggs don't hatch!

After day 26, you will stop turning the eggs. You will also need to increase your humidity to 85% at this time.
You still need to cool and mist the eggs after you stop turning them, just be careful not to move them! Goslings have very long necks that fold back on their bodies inside the egg. Moving them could cause them to get 'turned around', resulting in a failed hatch.

Problem Solving
Question: My goose eggs are shipped, how long do I let them settle? Do I need to turn them like with chicken eggs?
Answer: You should let the eggs settle after shipping for a minimum of 8 hours. Turning the eggs during this time should be avoided.

Question: My goose eggs are dirty, can I clean them?
Answer: Yes, it is possible to clean them. Use a damp, clean cloth and wipe the egg off.

Question: When can I candle my goose eggs?
Answer: By days 7-10 you should be able to see something, just like with chicken eggs. However, the shell of a goose egg is very thick. Unless you have a very good candler you will probably not see much.

Question: I have all the water wells full, and my humidity is still not high enough? How can I increase the humidity?
Answer: You can use a clean athletic sock soaked in warm water to increase the humidity. You can also add a piece of paper towel that is soaked in warm water. Remember, surface area is the trick when increasing your humidity.

Question: My goose egg has been pipped for a whole day! Do I need to help it hatch?
Answer: NO!! Helping a gosling to hatch is usually fatal! Goose eggs will often take 24-48 hours to hatch after pipping. Just sit back and try to control yourself.

Question: When misting, exactly what do you do? Do you actually spray on the egg?
Answer: Yes, when you mist the eggs, spray directly on the egg. Think of it as if you were the mama goose. You leave your eggs for a few minutes to go potty, eat, and take a quick swim. When you come back to your nest you aren't going to stand over the eggs for a while to let the water from your belly be over them, are you?

So, that's what I have for now! If anyone has questions please feel free to ask on the forum. Or send me a private message, if I don't know I'll find out who does!
Good luck, and happy hatching!!