Alltel's national freedom plans allow for free roaming as long as you are paying attention to your roam indicator on your phone. No cellular company has complete coverage across the nation... FCC regulation prohibit that. Therefore, Alltel roams with Sprint, Verizon, US Cellular, Cellular South, and AT&T (in the CDMA west only) to give customers nearly complete coverage. All of the above carriers also do this- this is nothing new. If you are not on one of these networks at the time, then your phone will display the appropriate roaming indicator-- a solid R or solid triangle at the top of your screen, meaning that you will be charged for using your phone in such area. Therefore, you, as the consumer, are responsible for watching your roam indicator when you are in an unfamiliar area. The fact that you made no mention of a roaming indicator tells me that you weren't paying attention to it... so, by what you've said, the charges seem valid to me.
I can tell you from experience that when many people are initiating service with Alltel, they are too busy looking at their new phone to listen to what the representative is telling them. People kill me when they claim they weren't informed of things when they got service. First of all, it is impossible for Alltel, or any other company for that matter, to inform you of every possible microscopic thing you need to know. If they compiled it into a book, you wouldn't have read it anyway. If people would spend less time tending to their neighbor's business, and tend to their own... meaning, start investigating your wireless service and get to know what you can and cannot do, then they would be much better off. I've been with Alltel for years and never had a problem. Grow up!