They want you to estimate how much money you think you will owe the IRS once the taxes are completed. In addition, they want to know if you have made any payments in 2008, estimated tax payments.
Also, you would have to give a little more info than what you have given. Is this for personal taxes, or a business????????
If it is personal taxes just go online and e-file before April 15, 2009 and you won't need an extension. If it is for business and you have a financial statement just take the bottom line, net profit/net loss and multiply that by 28% for federal and 5% for state and use that as the estimated tax due, until you get your taxes completed.