Normally I would recommend deep-frying the turkey, but at 23lbs I doubt you will be able to do this (the typical deep fryers are only for birds up to 15lbs to allow the proper amount of oil to safely be used).
I hope that the bird is fully thawed already...if not, remove it from the freezer NOW and place it in your sink with cold water. Change out the water every 30 minutes. You'll need about 30 minutes per pound to thaw the turkey out completely.
With such a large turkey, I would suggest brining to keep the turkey from drying out over the long cooking process (you can also use one of those oven bags that are made for turkeys as well - the skin won't get as crisp, but it will still brown nicely and the bird will stay more moist and tender).
Here's an easy brine recipe that I've had great luck with.
1 gallon vegetable broth
1 cup sea salt
1 tbsp crushed dried rosemary
1 tbsp dried sage
1 tsbp dried thyme
1 tbsp dried savory
1 gallon ice water
Place 4 cups of the broth in a pot and bring to a boil with all of the dry ingredients. Stir well to dissolve. Cool down completely and combine with the remaining stock and ice water. At this point I put the turkey in a large (CLEAN!
![Wink ;) ;)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
) garbage bag. (maybe I should mention also that you should always rinse the turkey beforehand and remove the bag of turkey parts and neck from inside the bird). Pour the broth in on top, close up the bag as best you can and place inside of a cooler with some ice. Let it sit overnight or at least 5 hours. When you're ready to cook, dispose of the brine - it's all turkeyfied at this point and you don't want to use it (plus it's salty as the ocean). Remove the turkey from the brine a couple of hours before you're ready to cook it - let it sit out and come up to room temperature.
You won't need much more seasoning, brush on a little melted butter and sprinkle the outside of the bird with salt & pepper.
Here's a link with turkey cooking times:
http://www.recipetips.com/kitchen-tips/t--910/turkey-cooking-times.asp
Do NOT use a disposable aluminum pan for a bird that size either - you're just asking for trouble - it will buckle when you remove it from the oven. Trust me.
Good luck!