We have got a couple of hacks which might help users from China in unblocking and accessing YouTube in their region. Some of these hacks and tricks have gone obsolete with time but most of them still do work.
Most effective of all remains the FreedomStick project which is basically a collection of pre-installed software that can be mounted on any USB flash drive and can be used to bypass any sort of firewall.
The FreedomStick project is specially focused towards helping users in China in bypassing the great Internet firewall which filters all traffic and information.
vTunnel, on the other hand, provides an in-browser proxy solution to access YouTube behind any firewall and watch videos. It is highly recommended for its good performance and high-speed streaming.
Also, UltraSurf is another light software proxy client along. For quite a different scenario, HotSpot Shield can be used to access Internet over a private VPN.
And if you know the URL of a video on YouTube, simply head over to Keepvid to download a copy of it locally to your computer and watch it without any restrictions.