Federal:

Internal Revenue Service http://www.irs.gov
Social Security Administration  http://www.ssa.gov/
Small Business Administration http://www.sba.gov

State of Texas:

Texas State Board of Public Accountancy    http://www.tsbpa.state.tx.us/
Texas Comptroller of Public Accounts http://www.window.state.tx.us/
Secretary of State  http://www.sos.state.tx.us/
Texas Workforce Commission http://www.twc.state.tx.us/
Travis County Appraisal District   http://www.traviscad.org/
Williamson County Appraisal District http://www.wcad.org/
Office of the Attorney General for the State of Texas https://www.oag.state.tx.us/

Associations:

American Institute of CPAs http://www.aicpa.org
Association for Certified Fraud Examiners  http://www.acfe.com/
National Association of Certified Valuation Analysts  http://www.nacva.com/
Texas Society of CPAs http://www.tscpa.org/
Austin Chapter, Texas Society of CPAs http://austin.tscpa.org

Other Resources:

American Institute of CPA 360 Degrees of Taxes  http://www.360taxes.org/
Accounting Today magazine http://www.accountingtoday.com/