S-1 forms detail a company's strategy for making money. Good place for business plans!
Go to EDGAR (the SEC database) and
1. Search Most Recent Filings
2. Limit to S-1 Form
3. Avoid the S-1/A (amendment forms) and read S-1s all day.
Now, one thing you can also do is go to the advanced search screen and type in a keyword (insurance, computers, etc.) and s-1. This should get you closer to browsing S-1 plans in your field.
Austin Business Journal- See what new businesses opened in the Austin area (and closed), who's hiring and expanding, and profiles of local business people.
Competitive Strategy - Michael Porter's crucial book about analyzing your industry and your competition. The building blocks for your plan. An earlier edition is here.
Encyclopedia of Emerging Industries
Entrepreneur Magazine - Profiles of new businesses and successful entrepreneurs
San Antonio Business Journal - San Antonio new businesses, expansions and successful businesspeople. See what they're doing.
Understand what urban planners are doing and how cities might grow. Future trends might spark an idea or two.