The state sales tax is 4.25%, but localities have a tax on top of that somewhere between 2.75 and 4.5%. New York City's total rate is 8.625%. Paul's page can get you this information, but for a simple table with all the information, look on the third page of this form.
As a side note, when they were introduced, all these fractions made it rather difficult for some businesses such as the one my sister worked for - how many cash registers are set up to calculate 8.625% tax?
