To the original poster: Your question isn't exactly clear.
If you are at full Social Security retirement age and are receiving benefits and are still working then for every three dollars you earn above the limit ($13560 in 2008 ) you'll forfeit $1 in social security payments. This is only true for the year you reach full SS retirement age.
If you are below full retirement age then you'll forfeit then for every two dollars you earn above the limit ($13560 in 2008 ) you'll forfeit $1 in social security payments.
When you are older thean full SS retirement age then there is no earnings penalty.
Here is the text from the SS website concerning the special rules in the year in which you retire:
Special rule for the first year you retire
Sometimes people who retire in mid-year already have earned more than the yearly earnings limit. That is why there is a special rule that applies to earnings for one year, usually the first year of retirement. Under this rule, you can get a full Social Security check for any whole month you are retired, regardless of your yearly earnings.
In 2008, a person under full retirement age for the entire year is considered retired if monthly earnings are $1,130 or less. For example, John Smith retires at age 62 on October 30, 2008. He will make $45,000 through October.
He takes a part-time job beginning in November earning $500 per month. Although his earnings for the year substantially exceed the 2008 annual limit ($13,560), he will receive a Social Security payment for November and December. This is because his earnings in those months are $1,130 or less, the monthly limit for people younger than full retirement age. If Mr. Smith earns more than $1,130 in either of those months (November or December), he will not receive a benefit for that month. Beginning in 2009, only the yearly limits will apply to him.
Also, if you are self-employed, we consider how much work you do in your business to determine whether you are retired. One way is by looking at the amount of time that you spend working. In general, if you work more than 45 hours a month in self-employment, you are not retired; if you work less than 15 hours a month, you are retired. If you work between 15 and 45 hours a month, you will not be consiconsidered retired if it is in a job that requires a lot of skill or you are managing a sizable business.