[CentOS] Skype on CentOS 5 - my microphone settings are incorrect

Note: The Wiki for Skype needs a tiny update.
http://wiki.centos.org/HowTos/Skype
It's not a Beta now. Last night, I downloaded and
installed skype-2.0.0.63-centos.i586.rpm
The Skype web site calls this a "Gold" release.

I'm having the same problem I had when I tried to use the Skype Beta.
It's not picking up audio from the microphone. The hardware works
fine, when I'm using MS Windows XP, but I hate to use Windows and
I use Linux, except when I want to use Skype or MS FrontPage.

I believe the problem has to do with a configuration setting. I use the
GNOME Desktop. 

In System > Preferences > Sound > Audio Conferencing > Sound Capture
there are five (5) choices: (a) CS46xx (b) ALSA (c) OSS (d) test sound
(e) silence and I get the following results when trying to test them:
(a) test and dies (b) test and dies (c) testing pipeline and I can stop
the test OK. I suspect OSS is the one to select (d) test sound = OK (e)
silence

In System > Preferences > Volume Control for Capture, I changed the
Device to OSS Mixer, but that doesn't cure the problem.

Selected as ALSA, I've tried it with and without the 20 dB mic. boost.

BTW, when I disabled the onboard Sound Chip and installed a very
inexpensive generic sound card in this Dell Dimension 2400 box, the
quality of the sound improved quite a bit.

Any suggestions on what configuration settings I should try, or any
other ideas, will be greatly appreciated! TIA!