• It's Fast. No more last minute trips to the Post Office - just hit Send!
• It's Accurate. The electronic tax filing program checks for errors and necessary information, increasing the accuracy of your tax return and reducing the need for correspondence with the IRS to clarify errors or omissions.
• It's Easy. The computer software leads you step-by-step. You can usually file a state tax return at the same time you electronically file your federal tax return.
• Get Quicker Refunds. Generally, when you file electronically, your tax refund will be issued in about half the time it would take if you filed a paper tax return. Those who choose direct deposit will get their tax refund in even less time.
• Get Peace of mind. Once the tax return is accepted for processing, the IRS electronically acknowledges receipt of the return.
• Have Payment options. With electronic filing, you can file your tax return early but wait to pay any balance due by the April deadline. You can also pay electronically, using a credit card, electronic funds withdrawal or, in some cases, the Electronic Federal Tax Payment System.
• Request your Telephone Excise Tax Refund. E-file can be used to request this tax refund.

Source: IRS.gov - IRS TAX TIP 2007