Here is a very basic HTTP client that uses the dispatcher class to implement its socket handling:
import asyncore, socket
class http_client(asyncore.dispatcher):
    def __init__(self, host, path):
        asyncore.dispatcher.__init__(self)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.connect( (host, 80) )
        self.buffer = 'GET %s HTTP/1.0\r\n\r\n' % path
    def handle_connect(self):
        pass
    def handle_close(self):
        self.close()
    def handle_read(self):
        print self.recv(8192)
    def writable(self):
        return (len(self.buffer) > 0)
    def handle_write(self):
        sent = self.send(self.buffer)
        self.buffer = self.buffer[sent:]
c = http_client('www.python.org', '/')
asyncore.loop()