improve this newbie code/nested functions in Python?

[Esmail]

Hi,

I'm new to writing Python code. This is a simple client I wrote, it
works, but I feel it doesn't look as clean as it could. Can anyone
make suggestions how to streamline this code?

Also, I am using two nested functions, it seems that nested functions
aren't used that much in Python - is that correct? And if so, how
come?

thanks,

Esmail

ps: I realize there is minimal error checking/exception handling.

#!/usr/bin/env python


import sys
from socket import *
from threading import Thread


class Client(object):
    def __init__(self, host="localhost", port=5555, name = "esmail"):
        self._host = host
        self._port = port
        self._name = name
        self._address=(self._host, self._port)
        self._sock=socket(AF_INET, SOCK_STREAM)
        self._sock.connect(self._address)
        self._parent = self
        self._keepGoing = True

    def info(self):
        return self._host, self._port, self._name



    class Listener(Thread):
       def __init__(self, parent, tname="listener"):
           Thread.__init__(self,name = tname)
           self._parent = parent
           print self._parent._host

       def run(self):

           while self._parent._keepGoing:
               m = self._parent._sock.recvfrom(1024)
               print m[0]



    class Speaker(Thread):
       def __init__(self, parent, tname = "speaker"):
           Thread.__init__(self,name = tname)
           self._parent = parent
           self._parent._sock.send(self._parent._name + "\n")


       def run(self):

           while(True):
               m = raw_input("-> ")
               if m == "bye":
                   self._parent._sock.send(self._parent._name + " is
signing off.\n")
                   self._parent._sock.send("bye\n")
                   self._parent._keepGoing = False
                   break;
               else:
                   self._parent._sock.send(m + "\n")


def main():

    if len(sys.argv) == 4:  # prog name + 3 args
        host = sys.argv[1]
        port = int(sys.argv[2])
        name = sys.argv[3]
        c = Client(host, port, name)
    else:
        c = Client()

    print "Client connecting to - host=%s  port=%d   name=%s" % c.info
()

    s = Client.Speaker(c)
    s.start()

    l = Client.Listener(c)
    l.start()


main()