
SCORE is a non-profit organization that partners with the SBA to provide counseling to small business. Current and retired executives donate their time to provide one-on-one as well as cybercounseling and workshops.

The Small Business Administration has an office in Chicago that helps with various programs and resources available through the SBA, including SBA backed bank loans and loans for disaster recovery.

This is the official portal for the State of Illinois. Information on registering a business, taxes, forms, licenses, etc. can be found here.

CCH provides an extensive toolkit for small business owners covering all aspects of a business plan, financing, managing, and more.
The IRS site provides information, publications, and forms on the federal tax obligations for small businesses including income, payroll and other taxes.