Using Skype from within China to call outside has been working fine for me and still is. The only VPN service which i know that has never been blocked or been down is Astrill (you can click my homepage link to get there). Its not free but for me its worth every penny.
Also, its abit dependant on your internet connection. We have 2 internet connections where i live. One 2mbps thats provided by the landowner, this one is from China Mobile and it has constant issues with foreign sites , skype etc. I went and bought my own ADSL from China Unicom a 3mbps for 1200rmb/year prepaid including wifi/modem/router. This connection almost never have any problem with foreign sites and blocked ones are easily accessible with Astrill. The speed is also A LOT faster then the other connection we have. No problems downloading or streaming videos.
China Unicom offers ADSL up to 8mbps right now but the speed of the service is very dependant of wehere you live. We could only get 3mbps where we live, although its still fine enough. If the Skype protocol gets blocked it will still be possible to use it with VPN services such as Astrill. However it will take a performance hit on the network load so if you are already having speed issues this might not work very good.
