It also has info on applying for (and negotiating a better) financial aid package from your college and estimating the cost of attending college. There is a section listing state financial aid resources as well.
Yes, the fafsa is crucial for getting financial aid. Make sure you complete it early and then go on to apply for financial aid. Search for scholarships, talk with the people at your financial aid office and apply. A lot of money is available - you don't get it if you don't apply.
One free guide on how to complete the fafsa is written by Chris Penn who al produces the FinancialAidPodcast. The book is a step by step instruction guide on how to answer each question in the FAFSA form. Some are harder than you think. Anyway, you can download the book for free at: www.fafsaonline.com/fafsa-guide-ebook.php
Oh yeah - you also have to apply for the stafford loan - you don't get it automatically...