I was experiencing problems with the microphone (in Skype) in Kubuntu Maverick 10.10: no input was received by the microphone, either in Skype or using the arecord. The soundcard is an
Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]and kmix was showing the capture device's volume at the maximum.
I don't know whether KDE configuration was spoiled by something, e.g., an update. However, I solved the problem by setting the capture source to the front mic, using alsamixer command line command (kmix does not seem to show any option about this).
So, if you have similar problem, run alsamixer from the command line, press F4 so that it shows only the Capture devices, set the volume of the capture devices (in my case Front mic) as high, and, most importantly, set the Input sources of capture (in my case Front mic).
Now your mic should work!