Payroll related web sites:

http://www.irs.gov/ - US Internal Revenue Services

http://www.irs.gov/pub/irs-pdf/p15.pdf - Circular E - Referred to as the "Payroll Bible".  This IRS publication contains employer tax information.

http://www.dol.gov/whd/flsa/index.htm - Fair Labor Standard Act (FLSA), Wages & Hour Division, US Department of Labor

http://www.dir.ca.gov/DLSE/dlse.html - California Labor Law - The Division of Labor Standard Enforcement

http://www.callaborlaw.com/ - California Labor Law Blog - Current posts on changes in laws affecting CA employment

http://www.edd.ca.gov/ - California Employment Development Department

http://www.americanpayroll.org/ - American Payroll Association