Your state business licensing/registration division is another good resource. Using networks such as LinkedIn can provide you with a wealth of information in your particular endeavor. Join groups and associations related to your profession.

I talk to my accountant, she is very knowledgeable about setting up new ventures.

With  SBA my business was either too big or too small, with the County Retired CEO's most of the information was outdated.

Advisory board of directors (or real board of directors)

Vistage Group ("CEO Club"); see www.vistage.com

Trustsed prior business associates that have gone on to other adventures

IRS websites

Professional association websites and BB

Search online

Other professionals in same/similar field

Other than the IRS websites, the problem is the reliability of the source.  I will always get a second opinion on something that I don't know is "gospel".  Sometimes, the problem is that you may have a question that involves more than one discipline-e.g. tax and law.  It can be difficult to get a complete answer to those questions.

my local SBA.

The interne and Biz Blogs

Business Week (magazine)

Wall Street Journal.

Washington Post (newspaper)

My bank and other admired business owners