Using Free File software
If your income qualifies you for Free File software, go to IRS.gov/freefile. Choose the option best for you, and you'll be directed to click through to the company's website. (You might save a step and go directly to the site of a provider, like H&R Block.)
You'll need to have a copy of your last tax return handy, along with your W-2 and any other documentation of your income and deductions.
Never used tax software before? It's incredibly easy and goes step-by-step through your return by asking a series of questions to fill in all of the blanks. At the end of the process, you file your return eletronically.
The IRS says you save time and will get your refund faster, particularly if you opt to have the money direct-deposited into your bank account.