rtlguru is correct.
If you sold in tax year 2008, depending on the type of sale, you will pay either short or long term cap gains or normal income at marginal tax rate. If you sell for a loss in 2009, that loss can offset any gains in 2009 or may be used to deduct $3000 from normal income and the remainder used to offset gains in future years or used to offset normal income at a rate of $3000 per year.