I have a question I live in the midwest (Illinois) and as everybody knows it gets cold here. This is my first winter storing my boat and while winterizing it I was wondering if its better to change the engine oil before storage or after the winter before it goes back on the lake?

That depends on the motor you have and the condition of your oil. I would recommend taking a look at your oil on the dipstick. If it smells like gas, or has any water in it (will look like mayonaise), I would change it. Do you know how many hours you have since the last change?
If your current oil is not contaminated with fuel or water, I would leave it and change in the spring. Don't forget to check your drive also. Here you are looking for water and/or metal flakes on your magnets. If the oil looks burned and stinks, change it.
You are always better off starting the season with fresh engine and drive oil, and gas.
Most of us with high performance engines change our engine and drive oil every 15 to 25 hours. If you are running a stock 496 or 502, you can double that service interval.
Steve

My engine is the 496 ho, my oil looks fine I have 33 hrs on the oil change and only 31 on the drive oil, I put full synthetic in the drive I think im going to change that every other year. So that would be like every 60 hrs. So I geuss If my oil looks ok then i will prolly just change it in the spring before use?
Thanks Steve

I would. With the changes in temp and humidity, you can get condensation in your oil, and fuel tanks. I forgot to mention fuel stabilizer too.
Regards,
Steve