I will try and make this simple, it is not, but long term capital gains are being taxed at a 0% rate to the extent they are less than the 15% bracket. Short term capital gains are being taxex the same as in 2007. On a individual you don't pay tax on the first $9450 of income ($3500 personal exemption and $5950 standard exemption) the next $8025 is taxed at 10% and the next $24,525 is taxed at 15%. during 2008, 2009 and 2010 long term capital gains up to $32550 of taxable income will be taxed at $0. so if you had total income of $42,000, all from long term gains, you would owe no tax. If you had the same income from short term gains you would owe $4,481.25. It becomes more complicated if you have other types of income, such as interes or dividends.
Consult your tax professional or dig out details on how it might effect you yourself