Tax Tools
IRS
For individuals: http://www.irs.gov/individuals/index.html
For businesses: http://www.irs.gov/businesses/index.html
California Franchise Tax Board
For individuals: http://www.ftb.ca.gov/individuals/index.shtml
For Businesses: http://www.ftb.ca.gov/businesses/index.shtml
Board of Equalization
Overview: http://www.boe.ca.gov/
Sales Tax by City or County: http://www.boe.ca.gov/cgi-bin/rates.cgi


