If you don't mind I'll critique what i've heard so far. If you do mind, then stop reading now.

The biggest thing that struck me is that her voice isn't very unique. I can hear flashes of what she sounds like naturally, but overall it seems like she's trying to copy another voice, mainly Natalie from the Dixie Chicks. I've been through the whole Nashville Star thing as a musician. A friend of mine tried out and I was able to accompany her on guitar in the later rounds. What they'll be looking for is something that stands out. Whether it's a great look or an interesting voice. She needs to relax and find her own sound. It's in there, and from what I heard of it i really like it.
The last thing is that she's out of pitch in several places. She holds the long notes well, but she tends to go flat on short notes in a run as well as accent notes at the end of the line. Sounds like she may be running out of breath. It's an easy thing to fix, she just needs to be conscious of it.
I hope I didn't offend. I've been working as a musician in Nashville for almost 10 years now. Everything I've said is a well intended critique and not a put down. I like the tone of her voice very much. She just needs to polish a few things and she'll be there!
I wish her the best of luck in the contest.
Cougar