I wish there was a way to answer this without sounding like I'm making fun of you, but I don't think there is.
You do know that talking is what you do on a phone correct? Do we need to ask if it's possible to talk on a phone these days?
If maybe you want to use Google Talk. look here http://www.google.com/support/talk/?hl=enhttp://www.google.com/support/talk/bin/answer.py?hl=en&answer=99030