No sound on Skype

Skype 4.3 needs PulseAudio, so I recommend you to install Pulse Audio Volume Control (pavucontrol) from the Lubuntu Software Center. or try:

sudo apt-get install pulseaudio 

Then it will be opened if you make a right click on the volume icon and choose volume control settings. It has a tab called recording where Skype will be shown if "Show Applications" is chosen while you are making a call, for instance a test call. It ought to show your microphone is working.

More instructions are described in this support webpage of Skype for Linux.

For all others who stumble upon this post looking for a solution to this problem and aren't very Linux/Tech savy just like me, this was my solution and I'll try to explain it as simple as possible.

I run Lubuntu 12.04, and I had the same problem. As the others mentioned above, Skype 4.3 no longer supports the ALSA sound driver (Too bad! I really hope they bring support back for ALSA! I personally like ALSA quite a bit better than PulseAudio.) and now solely relies upon PulseAudio as it's audio driver. As far as I'm aware Lubuntu (at least Lubuntu 12.04) doesn't come with PulseAudio, so you'll need to install that yourself. I used this code to do so:

sudo apt-get install pulseaudio

Copy that into the LXTerminal (located in the "start" menu - Accessories) and press Enter. Once the process finishes, PulseAudio should be installed and you can check to see if your Skype audio is working now.