A Breakdown of VPN protocols to Access Facebook in China
There's a bit of confusion going on about which VPN protocol to use to access Facebook in China. To tell you the truth, the best idea is to just find a VPN service you like, and ask them. Don't worry, I'll still go over some basic rules about choosing VPN protocols below, but the thing is that each VPN service is going to recommend different things, and some might not even offer service in China.
If you're using one of the standard operating systems like Mac OS/X, Windows XP, Vista, Win 7, Linux (Ubuntu), iOS (iPad/iPhone), Android, Windows Phone, or Nokia, you'll be alright. Pretty much every VPN service will have something for you. Anything else is kind of a toss up, but if you want to access Facebook in China on something other than the above listed, the recommended service is 12VPN. They've got tons of VPN protocols and can customize something that works for you.
Here's the break down of VPN protocols to access Facebook in China
PPTP
This is a pretty old VPN protocol, and it's security features are pretty lame. It works outside of China, and to some extent in China (blocked in some areas), but there is no VPN service that will recommend this for users in China. If they do, they're dumb and don't know what they're talking about. I don't see any reason to use this in China.
L2TP
Previous blocked in China (along with L2TP), if you get this VPN, you're taking the risk that it will be blocked again. L2TP offers many security improvements to PPTP. The thing with this VPN protocol is that you'll be able to install it on your smart phones (iOS/Android). For phones, you always have the option of a web based proxy, but for those who prefer to use VPNs this is an 
option. Again, because it's a risky protocol for users in China, many services offer a kind of "VPN cocktail", or a kind of custom VPN setup for customers who want to use a VPN on their phone in China.
IPSec
This has a couple definitions. It sometimes refers to the security features attached to an L2TP VPN setup, and sometimes can be used alone as a way to unblock sites like Facebook in China. 12VPN offers this as an option for smart phone users in China.
SSTP
Some VPN services offer this VPN protocol, and some don't. It works in China, but only on limited operating systems. It currently works only on Vista and Win 7. It's a Microsoft product, and Vista/Win 7 OS come with VPN clients to support SSTP. This means that setup will be faster that OpenVPN, which can also be used. As more users begin to switch from XP to Win 7, we may see more companies start to offer SSTP options. One 
of the only places to get this in China is with PureVPN.
OpenVPN
OpenVPN is the most versatile of VPN protocols, and can be use on any Windows operating system, Linux, and Mac OS/X. You've got to install 3rd party software, but it's free. It's combined with SSL encryption, making it probably your strongest choice for avoiding big brother. Not only will you be able to access Facebook, but you'll be able to watch Hulu and Netflix movies/TV, stream video without dropping connections, and keep you IP anonymous in any situation. This is the preferred VPN protocol for users in China.
IKEv2
This guy kind of comes out of left field, and for Nokia phone users in China, you'll be able to use this in combination with mVPN, which is a free download for Nokia users. The best place to get this is 12VPN.
Recommended VPN services
PureVPN in China http://purevpn.com
12VPN in China http://12vpn.com
