Hi agran,

If the webcams you purchased does not have a built in mic, you can use a separate microphone plugged into the mic input on the back of your computer. Any old mic will do.

On your question about speakers, headphones are not required, but it is recommended so folks on the other ends don't hear an echo of themselves.  If you choose to use speakers, keep the microphone as far away from the speakers as possible, and keep the speaker's volume at a lower level. If your chat software has an anti-echo feature, I encourage you to activate it.

Best of luck to you, and enjoy your web chats!

Mind Over Matt'er - Technology musings, opinion, and more straight from TechLore's head geek.