Federal

Electronic Federal Tax Payment System
Federal Forms and Publications from the IRS
I Can! e File - "a FREE online program that will help you fill out your federal tax forms while determining if you qualify for the Earned Income Tax Credit."

State

Alabama Department of Revenue
Links to State Forms from the Federation of Tax Administrators.
I Can! e File - "a FREE online program that will help you fill out your federal tax forms while determining if you qualify for the Earned Income Tax Credit."

General Information and Guides

1040.com - tax information, forms, and more
H&R Block Tax Tools and Reference
MSN Money Tax Page
Tax Preparation Guides and Services - from RefDesk.com
Tax Scams -  - How to Recognize and Avoid Them
Yahoo Finance Tax Center
Your Federal Income Tax for Individuals - IRS Publication 17 (PDF)
Tax Tips 4 You - an excellent page from the American bar Association, with information for the individual, small businesses and the self-employed, charitable organizations, and other links to government agencies and consumer groups

For Families

Tax Information for Parents
Earned Income Tax Credit (EITC)
Education Credits
Topics for Parents

For Older Americans

Tax Counseling for the Elderly
IRS For Seniors & Retirees
AARP Tax Aide

For Small Business and Self Employed

Small Business and Self-Employed One-Stop Resource