I am not an attorney and not a CPA.
Look carefully at your check stubs or copies of the checks. If your were being paid as an empoyee then you should have had FICA (or medicare and Social Security), Federal Income tax, State income tax (depnding on state), Local income tax (depending on state), School district tax (depending on state), and various other local or city taxes.
If your employer, for whatever reason, does not supply you with a W2 then you should be able to create one yourself either from your last paystub with all of the year-to-date information (sometimes labled YTD) OR you can manually add all of the information. However, it is his legal obligation as your employer to provide you with a W2 that is hand-delivered or post-marked by January 31, 2001.
Alternately, if you are NOT an employee and are infact a subcontractor, you CAN elect to have federal tax withheld OR if you were tardy in filling out a W9 form--information for a subcontractor's social security number and address--the vendor is REQUIRED by law to withhold 15% of your earnings for federal taxes if they estimate that you will earn more than $600.00 for the year.
Now, if you are a sub contractor, the vendor is required to give you a 1099, which is similar to a W2. It also must be hand-delivered or post-marked by January 31, 2001. They are required to give you one of these if you earned more than $600.00 in one year and you are not a corporation.
Sorry for the VERY long reply. If you have trouble determining this information alone I would advise consulting an accountant. Please note that you might have had some uniform dedutions or something that lowered your check, but taxes were not actually taken out.