For anyone who has struggled with audio issues using Skype 4.0.0.7
Using SUSE 12.1 on an Acer Extensa with Realtek ALC268 card.
I had terrible microphone input sound with Logitech C270 Webcam - though it worked fine with Skype on XP
The problem was garbled sound/ excessive crackling to the point of not being able to hear my recorded voice on a test call.
After experimenting with Audacity to check recording capability - I realised there was a relative simple fix.
I used pavucontrol configuration tab to set my sound card from analog stereo duplex to analog stereo output.
This completely solved any audio crackling/distortion in Skype
I hope this helps anyone else who has similar issues.