The IRS has stopped mailing out tax booklets and forms. You can download the forms, instructions and various publications directly from the IRS.gov Web site. The IRS also has recently re-designed their forms and publications page. In the redesign, the most common forms and instructions have been placed near the top of the page, making it easier for taxpayers to find and download the files they need. The IRS has also redesigned their archive page for tax forms from previous years. I've had trouble finding specific files using this page, and I much prefer utilizing this page that organizes forms by year.
Also updated is the About.com page providing links to the most common federal tax forms. You can locate state tax forms by navigating to your state tax agency Web site and then searching for the forms you need.
You may also be able to find paper tax forms at libraries, post offices and local IRS offices.