It's April 18th, and your taxes are due. If they're not ready, that's not the end of the world. The IRS has seen and heard it all, and they know this happens. Here's what you need to know about filing for an extension.
If you need an extension, you can use IRS Free File to ask for it by midnight by going to the website and filling out the e-file request form. Then you have until October 17th to finish up.
The classic option is to use Form 4868, which gives you an automatic extension to file. Since you have to mail this form by April 18th, it's due when the post office closes.
If you think you owe taxes still, you can use IRS Direct Pay, online or by phone, which lets you pay from your bank account. This option automatically tells the IRS you're going to be late, so there's no need for a Form 4868.
Sometimes, it's not the filing that's the problem but rather ponying up the cash. If this is the case, the IRS recommends you file on time and simply pay what you can. In that case, you won't get a penalty for a late return, although you can still get fairly hefty penalties for not paying. The IRS even recommends getting a loan or taking on credit card debt to pay, because even those interest rates might be more desirable. In some cases you can even get on a payment agreement for installments.