I finally got VLC to play a DVD by entering Device name as "/dev/dvd" but there is no sound. This is a little puzzling because Xine plays the same DVD fine, with good sound.
EDIT: I needed to adjust the setting for PCM with KMix; PCM was set at zero. Now at 90% or so, I have sound with VLC.
To play an Audio CD with VLC on VL 5.8 SOHO, you accept the default Device name as "/dev/cdrom". The tricky part is that the default value for Track is "0", and you must increment that value to the total number of tracks on the CD. Then click OK to close the dialog. When configured in this manner, VLC starts up playing the last track, so to play Track 1 first, you must move the slider to the far left.
EDIT: Another way to handle the Track value is to set it to a number greater than the actual number of tracks, for which VLC starts playing at Track 1, thence to Track 2 and so on. ("30" usually works)