I used TurboTax.com to file my federal tax return electronically. I filled in everything they ask me, paid the preparation fee and submitted the return electronically. When I read the .pdf file of the 1040 (and related forms), I realized TurboTax included some vouchers (1040-ES) for me to pay 'estimated tax' for year 2006. I don't think I have ever indicated that I want to pay estimated tax for the next year in this year's return. However, I already submitted the return. Do I have to use those vouchers to pay the estimated tax in 2006 (there are 4 installments)?