Actually, that number rises slightly every year.
If all your income was from the same employer, they should automatically stop. It is a feature of most of the automated payroll systems.
*edit, looked it up: 90,000 for 2005 (max tax: 5580), 94,200 for 2006 (max tax 5840.40).
From FAQ from SSA.gov:
"I worked more than one job during the year and paid too much in Social Security tax. How do I claim a refund?
When you have more than one job in a year, each of your employers must withhold Social Security taxes on your wages without regard to what the other employers may have withheld. You may then end up with total Social Security taxes withheld that exceed the maximum. You can claim a refund of the excess taxes that were withheld on form 1040 when you file your personal income tax return with the Internal Revenue Service.
You should contact the IRS at
http://www.irs.gov for more information on how to claim a refund of overpaid Social Security taxes."
~faith,
Timothy.