I recently did a fresh install of Ubuntu 13.10 64-bit on my HP Compaq Pro 6305.
After installing a few of my most used applications, I went and installed Skype.
I logged in and tried to test the sound and microphone, here's where my first problem occurred. It would not hear me at all, and my microphone worked fine on Windows. I went into Skype options and my only sound and recording device choice was PulseAudio, and I constantly have problems with that (although I think those times were my fault) but I had just installed this and it was already messing up on me.
This is where my second problem happens. The sound continues to work fine most of the time, except for every so often when it starts crackling, and in some cases the whole thing just starts making a weird high-pitched buzzing noise that won't stop unless I restart Skype.
Both the 32-bit .deb install and the multi-arch .deb install do this for me. It's a headset + microphone from Cyber Acoustics if that means anything as well.
I'm really not sure what else too say, I hope you can figure something out based on that info.