Ultra surf is a proxy tool which will let you surf Internet via proxy. You need to change your internet connection settings to access websites including Facebook.
Your-freedom is again a useful piece of software to access any blocked website. Though it’s free version has certain limitation like bandwidth caps and concurrent connection stream, but to access few sites like Facebook it will be very handy.
There are many VPN software’s which you can use to access internet using other IP. This way you can access any website which is blocked by your internet service provider or by your Firewall. Provided you are able to connect to that VPN server. One such VPN software which you can use is Astrill VPN.
This is most common way to access any blocked site and you can search in Google for keywords like “Working proxy sites” “Unblock facebook” to find working proxy sites to access Facebook.
I’m sure many of our Pakistani friends will find it useful as it’s not decided how long this ban is going to stay in Pakistan. Do let us know your reaction about ban of Facebook in Pakistan and do share any more working ways to access Facebook in Pakistan.