This is a question for me too. I would imagine myself in a new church with a group of people who had never sanged in choir, so in my imagination what would I do?
1) Audition
*make sure they can match pitch. If they can't match a pitch
it'll be difficult to hold a part. A simple scale(do, re, mi,
fa, so, la, ti, do). I'd do it as a whole group excercise.
Start on a low note and half step upward. Reverse the
excercise downwards in half steps. Do it a few times and listen
well, you'll hear alot.
2) Test song
*Choose a song with highs and lows. The National Anthemn is a
great one. Let each one do it without instruments. This will
give you an indication of their range ability, flexibility and
possibly where they may be classified. The song also will also
test what I call the "shy factor". If they are to shy to sing
-then they may lack the confidence that is required for minis-
try.
3) Remember that voice classification is genderless. There are female
Tenors and males who can sing Alto.
4) Remeber during the test song make notes about possible classi-
fications.
5) Review your notes. At this point you may want to place them or
wait to pray and talk to people individually. Choir is more than
singing only.
6) Once placed, realize that you may have to still move people around.
7) Once you feel comfortable that we're all in our places with bright
shiny faces then you can start working.

Learn what I call "choral foundation" pieces(check hymnal)
*Hear Our Prayer O Lord(modulate thru 3 or 4 keys)
*Lord's Prayer (chant)
*Gloy BE To The Father(modulate thru limited # of keys)
*Threefold Amen(modulate thru 3 or 4 keys)
warming up with these will help keep a purity and crispness of
sound; and help them to hold parts consistently
9) Don't let them get lazy.
10) They're not perfect. Maintain standards, but be realistic. Most
of all do it with humor and have FUN! Holla!
P.S.
Don't be afraid to weed out some folks, because kicking the crazies to the curb now saves a lot of trouble later.