The Small Business Administration is a good place to start for business planning help.
http://www.sba.gov/
SCORE is another resource:
http://www.score.org/
Grants are obviously a difficult thing to come by. When shooting for grants and angels (very early investors in a business) your goal(s) have to resonate with those who are giving the grants and loans in a big way. Not that it can't happen but it's a very difficult route. Unfortunately, if the business is more along the non-profit line then that's likely the best way for you to go since banks and other venture capitalists want to know what's in it for them and they're usually only interested in businesses that can show at least some history of sales.
As far as where you can go to get grants, it will really depend on the business you're looking to open.
I have a fair amount of experience in the corporate world with developing business plans, targeting customers, and creating business case models. I'll gladly offer whatever guidance I can.
--Paul