https://axon.dolby.com/
I highly recommend getting this. It's continuous like skype. But it doesn't muffle the other audio on your computer. It allows for proximity meaning that the side that a person is on (in relation to you) is the side that their voice will come out of your headphones/speakers. It also lets you create up to 5 permanent channels that can hold any number of people, and it is all free. The biggest thing it does is use less bandwidth than skype (A LOT less) and it requires less processing-- meaning smoother gameplay :).

The creaters of dolby axon are the same people that bring you dolby surround sound and other dolby products-- meaning that its not some random 3rd party communications program.

Tell me what you think and if you decide to try it out add FilthyJack to your friends list.