Great advice about how to sing in the choral style
Think about the voice as an instrument as you watch and listen to these:
Notice that the voices are perfectly blended. No one voice sticks out.
This group is from North Dakota and Minnesota. Most are not professional musicians, but have been taught to sing and they sing because they love to. The song, "Dum Transisset Sabbatum," is composed by John Tavener. Tavener was from England and lived from 1490-1545.
This is a really great group called Scala. They are singing Metallica's "Nothing Else Matter's in the choral way of singing.
For comparison, this is the original "Nothing Else Matters" by Metallica. This is definitely not choral singing, but it's great!
I just listened to this next one for the first time (11/02/14). It's amazing and makes me (and hopefully you) want to explore choral music further.