How to chat using webcam?

Normally, when you go to a site which allows web cam chat (Some examples would be chat roulette or omegle, just Google them and you'll find them) and you have a functioning web cam, a box will come...

Yes, yes you can !! just as long as you have Wi-Fi and you have internet in your phone :)

To do this you need to use an application that joins two (or more) people with webcams together across the Internet (e.g. Skype, AIM or Google Talk).

If you are underage, and the people who download your image are adults, that can be a serious criminal offense for them if the images constitute child pornography under the law. I don't know whether...

Yes, you can. You can use the Windows Live Messenger to "instant message" other people.