The Amazon.com rewards card was my first credit card, so no, I'd say you don't have to have excellent credit. I had $20K+ in student loans with only about $150 in interest paid off at the time and they approved me almost instantly. (This was only a few months ago - August or September.) Only a $1000 credit line, but not too bad for a first card. I'm enjoying the rewards points since most of what I buy is on Amazon anyway.
This is a pretty awesome deal, thanks for letting us know! Good until the end of December, too -- I know I'll be buying more Kindle books come Christmas!