First of all, you have to have a computer with an internet connection and administrative rights.
After you've met all initial requirements, proceed to step one.
- Go to CallCentric.com and sign up for a free account. You can use a fake email addres for this, for example I use the website 10minutemail.com. Enter the requested details and confirm the registration with the new email that you will receive. Agree to the terms (read them if you want) and click "Sign me up". Step one status: done.
- If you now log in to your CallCentric account, you will notice your newly assigned SIP phone number in the form of 1777** where ** is a sequence of digits. Write this down or save it to a .txt file for later use. Step two status: done.
- Go to phone.ipkall.com and get yourself a real US phone number based on the information from your CallCentric account. I recommend using the same username, email and password for the sake of simplicity. In the field asking for a SIP username, write the previously copied SIP number. In the hostname field write "in.callcentric.com" without the quotes. Step three status: done.
- While you wait for a confirmation email from IPKall, download and install Express Talk (available for Windows and Apple OSX). After the installation run the application. You will be asked to fill in the information of your SIP account. Enter the SIP number of your CallCentric account, the same password you used there and for hostname, enter "callcentric.com". (Note how you must not write the in. prefix here. If you do, it won't work.) If all went well, Express Talk should successfully connect to the server and if you go to your CallCentric account, you should see a note saying "Your phone is registered". Step four status: done.
- Find a proxy listing site, for example I used this one. Make sure the proxy is using the port 80 and is stationed in the US, otherwise it will probably not work. Assuming you use Firefox internet browser on Windows, to use a proxy you must go to Tools -> Advanced -> Network tab -> Connection -> Settings... Here you select "Manual proxy configuration" and input the proxy IP and port number. Also check the option "Use this proxy server for all protocols". Confirm the settings. To verify that you are successfully connected to the proxy, go to ip-adress.com and it should show your location somewhere in the US. If the proxy doesn't work, try another one from the list. Step five status: done.
- Now is the time to finally set up a Google Voice account. While still connected to the proxy go to voice.google.com and log in with your Google account. If it says that Google Voice is unavailable in your country, delete your cookies and try again. If all goes well you should see a frame asking you to choose your very own Google Voice phone number. Search around for a bit until you find a number to your liking. In the next step choose a PIN number and write it down somewhere in case you ever need it. Next, enter your IPKall number that you previously registered, and click "Call me now". Hopefully Express Talk should ring and you can press the required numbers. This concludes the registration. Step six status: done.