Initiate a Click2Call with your Google Voice account, from the command line. Your phone will ring, and when you answer, you will be connected to the number you specify (using the t: argument; see Usage below).
This script will try to write in cookies.txt, so make sure this file exists and is writable, or that the user running the script (apache, http, nobody?) has the necessary permissions to create that file.
It also needs simplejson: sudo easy_install simplejson (or modify the simplejson import to just import json, if you use Python 2.6+), and Mechanize: sudo easy_install mechanize
And evidently, you will need a valid username and password that has access to Google Voice.
GV_USERNAME is the (@gmail.com) email address, GV_PASSWORD is pretty self-explanatory, and you will want to define a GV_CALLBACK_NUMBER phone number (that starts with +1), which is the default phone number that will be called first during the Click2Call handshake.
If you don't define a default GV_CALLBACK_NUMBER, make sure you call this script with a f:... argument, to define the callback number to use. That number needs to already be defined in your Google Voice settings.
python google-voice-click2call.py f:+15145551212 t:14181234567
f: defines the callback number (your own number). It is optional if you define a default GV_CALLBACK_NUMBER in the script. It should always start with 1+
t: defines the number you want to call (the third-party number). This argument is mandatory.