Surely, the webcam will come with software if needed for basic functioning of the webcam; I don't know whether some webcams come with some kind of web conferencing software, but NetMeeting would work.
"built in mic"? Oh, I don't know. As long as you have some type of mic, that should work. I really haven't done much web conferencing. My inexpensive webcam came with a mic that attaches to my ear. That works OK but I imagine one that sits in front of you would be easier to use.