Dave,
Most likely you would access Alaska Communications Systems.  They are a
TDMA carrier so you should be roaming on analog.  They have good
coverage in the area:

http://www.acsalaska.com/wireless/calling_areas/southcentral.stm

You will be charged roaming if you have the AC plan.

-Bill Radio

Western U.S. Wireless Reviews & Ratings:
http://www.MountainWireless.com

dave@newrivergroup.com (Dave Christensen) wrote in article
<bl9s6h$9tpf9$1@ID-17425.news.uni-berlin.de>:

I was up there with my Verizon AC cellphone, and it worked great for analog
voice in most places, there were a few digital things that didn't work (like
data stuff, and voicemail), but just for kicks, I was in a plane at 18,000
feet over Mt McKinley, on Top of the world highway (near Chicken), on a
catamaran in Prince Edward Sound, and on a ship going down the inland
passage on the Alaska marine highway, and called a friend of mine. <I like
to call from strange places, you know.. call and ask "Can you hear me
now?"... now if I could just get Verizon to subsidize my next trip