Finding a reliable website that has grant information can be hard with all the websites out there. One of the biggest grants I know of is the Pell Grant and to find out if you are eligible for it you have to fill out your FAFSA. I used Pell Grants myself for school. Another great source of information on grants and scholarships is the school you are going to be attending. Talk with their financial aid or admissions department to see if they have any funding options that you qualify for. They may have some based on your grades and major or just need based help. Also, if you have a job with a large company, such as Best Buy, they may also offer a scholarship program as well. Check with your human resources department. I found this article that I thought had some interesting information - http://www.collegescholarships.org/grants/. This website offers reviews of the top scholarship websites and should help you decide which one(s) you want to use for your search - http://www.starreviews.com/college-scholarship-site-reviews.aspx. I will say that I used FastWeb, but the downside of the ads can be annoying.
Please let me know if you need more information.