Simple Python script uses cURL to make a txt file with your devices external IP address. After that, you can email it, tweet it, or anything you want. I use this with my Raspberry Pi, and a Twitter bot

external_ip_output.py

import os
def erase_file():
    with open('/home/user/external_ip_output.txt', 'w'):
        pass
def get_ip():
    stream = os.popen('curl ifconfig.me --max-time 7 -o /home/user/external_ip_output.txt')
    return stream
def open_file():
    f = open('/home/user/external_ip_output.txt', 'r')
    text = f.read()
    f.close()
    return text
def main():
    got_ip = False
    while got_ip is False:
        get_ip()
        text = open_file()
        if len(text) < 1:
            print "Timed Out."
        else:
            print open_file()
            got_ip = True
erase_file()
main()