Free worldwide SMS sending script using Solinked API

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Free worldwide SMS sending script using Solinked API.

import sys
import requests

forge_user_agent = 'Mozilla/5.0 (X11; Linux i686) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5'
script_url = 'http://solinked.com/solinked/sendsms.php'
forge_headers = {
    'Origin' : 'http://solinked.com',
    'Connection' : 'keep-alive',
    'User-Agent' : forge_user_agent,
    'Content-Type' : 'application/x-www-form-urlencoded',
    'Referer' : 'http://solinked.com/',
}

def sendsms(destphone, smsbody):
    resp = requests.get('http://solinked.com/')
    forge_headers['Cookie'] = resp.headers['Cookie']
    html = resp.text
    numberfield_key_pattern = r"' id='no' class='no'"
    checkfield1_key_pattern = r"' id='on' class='n0'"
    checkfield2_key_pattern = r'" class="formsend"'
    numberfield_end_pos = html.find(numberfield_key_pattern)
    checkfield1_end_pos = html.find(checkfield1_key_pattern)
    checkfield2_end_pos = html.find(checkfield2_key_pattern) - 41
    checkfield2_val_end_pos = html.find(checkfield2_key_pattern)
    numberfield = html[numberfield_end_pos-32:numberfield_end_pos]
    checkfield1 = html[checkfield1_end_pos-32:checkfield1_end_pos]
    checkfield2 = html[checkfield2_end_pos-32:checkfield2_end_pos]
    checkfield2_val = html[checkfield2_val_end_pos-32:checkfield2_val_end_pos]
    reqfields = {numberfield : destphone, checkfield1 : '', checkfield2 : checkfield2_val, 'mymessage' : smsbody}
    resp = requests.post(script_url, reqfields , headers=forge_headers)

if __name__ == "__main__":
    if len(sys.argv) < 3:
        print "Usage: solinked [num in international format with 00 instead of +] [message]"
    else:
        sendsms(sys.argv[1], sys.argv[2])
        print "Message sent"