The personal tax allowances are announced in the March budget, delayed this year until 22 April. The new tax code 647L for 2009 is already known.
The standard personal allowance effective from 7 September 2008 was 6,035 being the tax code 603L. From 6 April 2009 the new tax code will be 647L representing the new personal allowance of 6475.
The new 647L tax code can be applied by employers from 6 April 2009.
Current income tax rates and allowances are posted on the HMRC website at
http://www.hmrc.gov.uk/rates/it.htm