If half of your SS benefits plus other taxable income is less than $25,000 - none of your SS is taxable,
- if more than $25,000 - part of SS income will be taxable - you would need to fill the worksheet to calculate the exact taxable amount. The maximum is 85% of your SS income.
as you are below the full retirement age you may earn up to $13,560. If you earn above the limit - your SS payment will be reduced $1 for every $2 you earned over the limit.
For 2008, that limit is $13,560. For 2009, that limit will be $14,160.