Pull out the radio and check the fuse on the top right corner of the radio. It's a blade fuse, you can't miss it. Hopefully that's the problem.
When mine went out in the '03, though, I had not started the car for almost a month and a half, and the battery was dead dead dead. (I bought a battery tender that weekend)

. I charged the battery, and everything else came back to life, but the radio wouldn't turn on, just like yours. I also checked all the fuses, including the back of the radio one, and all was good. So I took it to the dealership, where they installed a new one under warranty. My SA's explanation was that "we get a lot of the NB radios that die after a battery failure." He may just have been trying to make me feel better, but he's always been truthful with me before (I've bought several cars from them). I hope you have a happier end result...
