I first heard of Goapele (pronounced gwa-pa-lay) from Honey Soul, the same place where I'm continuously updated on all good music that doesn't get played enough on the radio. I promptly searched for her on Last.fm and fell in love with her gorgeous voice. You can download several of her more popular songs for free on her website. My favorites are "Closer", "Don't Be Shy", "Milk and Honey", "Back To You", and "Chocolate".
Here are samples of her first two albums:
And here's her new music video for the song "Milk and Honey", which is an example of appropriate use of auto-tune.