Tony, that is true if you are talking about taking the deduction during a year when you have no capital gains.
For example, if you have a $30k stock market loss in 2008 and no stock market gains in 2009, you would be correct and the $3000 limit would apply.
If however you have a stock market gain in 2009 of lets say $15k, you would be able to apply that 15k gain against the prior $30k loss. That would result in no tax for 2009. And then you would carry over the remaining prior years loss to future years.