Well, if you're PC's mic is built in, like mine, everything's ready to go. What most people don't know though, is that there's push-to-talk. I don't know what the key command for talking is since I use a controller, but it's right on the dpad if you do use one. I just turn off push-to-talk though. I can't stand having to hold a button if I want to talk.
PSN:syluxrules DCUO: HardLight Assasin-Hero USPS3 Controller and proud of it