According to the 1911census.org website some limited info will be available in 2009 but all sensitive material will not be released until Jan 2012.
You can for �45 buy some info now but there have been complaints about whether it is worth the cost.
The same website says that even though the 1911 census is being released early, the 1921 census is free from the ruling and will be governed by the 100 year rule.
The 1931 census was completely destroyed by a fire so no info is available for that at all