In no particular order.
Plenty of business plans to review for all sorts of businesses, as well as an opportunity to purchase some software.
Business Plan Blog
Some good tips on this page in an easy-to-read format.
Centre for Business Planning
Masses of free information, examples, resources and links.
Microsoft has put a lot of effort into helping you get your business going and this page is a good starting point.
An Australian Government initiative which 'offers you simple and
convenient access to all the government information, transactions and
services you need. It's a whole-of-government
service providing essential information on planning, starting and
running your business'.
Business Owner's Toolkit
Describes itself as 'Total know-how for small business and entrepreneurs'. Type 'business plan' in the search window to take you to essential links.
A site for business planning software.