IRS rate of exchange?

What is the IRS official rate of exchange for filing my 2010 taxeds please? 

From http://london.usembassy.gov/irs/irsxchng.html: "The IRS has no official exchange rate. Any posted exchange rate that is used consistently is acceptable."

They then go on to post an unofficial exchange rate of £1 = $1.54.

You can use this rate or you can use a generally available exchange rate from a commercial website such as xe.com or oanda.com. As long as you are consistent in the rate you use you will be fine.

What i tend to do each year is look at the mid-market exchange rate on each payday for the year.  I think you can look it up searching on oanda.com

Thank you !!