Skype has certified the Sennheiser PC series headsets. You know, just in case you didn't already know that Sennheiser makes top-notch headsets, and you needed to hear it from a company that provides VOIP that sounds like someone speaking inside a tin can piled under eighteen heavy rugs. Okay, Skype isn't all that bad... The VOIP provider also certified IceMat's $79 Siberia Multi headsets, and announced that its products will be sold at Radio Shack as well as online. Given Vonage's handset news yesterday, Skype had to do something.