A.M. Best
Insurance company directory and ratings service.
http://www.ambest.com/

The Insurance Industry Internet Network
Directory of insurance carriers and their web sites, divided by category.
http://www.iiin.com/iiincompanies.html

Agents Insurance Marketing USA
Lists major life and health insurance companies, and annuity companies, with links and information on each company.
http://www.agent-central.com/lifeco1.htm

Insurancelocal.com
Find the insurance companies with web sites.
http://www.insurancelocal.com/insurancecompany.htm

Insurance Information Institute
Offers mailing address, phone numbers, email and URL links to major risk and property insurance web sites. Other insurance information on the site is quite useful.
http://www.iii.org/media/companies/insurance/

Help insure me
Insurance directory with a difference. Tells users where to look depending on their own individual profile.
http://www.helpinsureme.co.uk

NCCI Holdings, Inc.
Direct links to most companies on the web.
http://www.ncci.com/nccisearch/contact/strategiclinks3.htm

InsuranceStates
Provides links to information and services from insurance companies, agents and brokers by US state.
http://www.insurancestates.com/directories.html

Americas Health Insurance Plans (AHIP): Links
List of health insurance companies in the USA.
http://www.aahp.org/Content/NavigationMenu/About_AAHP/Who_We_Are/Health_Plan_Member_Links/Health_Plan_Member_Links.htm

Search4finance.com
A four page directory of insurance carriers.
http://www.search4finance.com/insurance.html

Insurance Professional
List of USA property and casualty, life and health insurance companies.
http://www.einsuranceprofessional.com/inscomp.htm

Mobileshoppee (INDIA)
Insurance carriers serving India
http://www.mobileshoppee.com/insurance.php

American Insurance Depot
Directories of company websites and US state insurance commissioners, plus other resources for finding insurance companies that issued old policies or resolving complaints.
http://www.americaninsurancedepot.com/

Insurance Agencies By States
Directory of insurance agencies organized by states.
http://www.insurancestates.com