The Association of British Drivers
Fuel Tax Calculator
Tax Rates (1 September 2009 to 30 March 2010): HMRC
(N.B. This URL changes often, probably to make it difficult to find. Last time we found it by searching for "Hydrocarbon Oils", which is of course the first thing anyone would think of.)
The above are just taxes on fuel — don't forget there are a plethora of other stealth taxes imposed upon drivers: