I had posted a similar question here a few years ago and got some good suggestions.
I also liked the book “Talent is not enough”as a resource,
and also found
“Business and Legal Forms for Designers”
http://www.amazon.com/Business-Legal-Forms-Industrial-Designers/dp/1581153988
very helpful.
“The Designer’s Guide to Marketing and Pricing”
http://www.amazon.com/The-Designers-Guide-Marketing-Pricing/dp/1600610080/ref=sr_1_1?s=books&ie=UTF8&qid=1332376700&sr=1-1
provides good basic business advice, even though it is more geared towards graphic and web designers.
One of the authors, Ilise Benun, has a website with free resources and regular newsletters and podcasts:
The British Design Council also has good resources (some of the legal information will be based on UK law):
http://www.designcouncil.org.uk/resources-and-events/Designers/Guides/
I like Stay Youth’s tip with the local small business admin office. I meet with a business adviser once a month to discuss non-design related business issues.