Yes, it is most certainly possible to record your friend's voices. Download a program called Bandicam and choose the primary drive with primary sound capture driver. With the secondary sound device, choose Win7 sound.

If you do what Finnish said, it will record any other sound coming from your computer.

If you're not doing anything in the background, that is a good way to do it.

Although if you are, you might want to look for a Skype sound recorder.
I know there are some but have never tried them myself.

Also, there's a program called 'Virtual Audio Cable'.
Look for tutorials on the internet for how to use it.

But, when you figure out how to use it, set your Skype sound to play through a 'line' you created.
Then just record that 'line' with something like Bandicam, Fraps or even Hypercam would do.
Or even the 'Sound Recorder' that comes with windows would do!


Hope I helped!