Don't get side tracked with all the commercialism that is associated with grants: Start with the source
www.grants.gov and if you have a good deal of time set aside, go down each topic top to bottom on the left side of the web site. There is a registration process you have to do even before the arduous process of applying for a grant. I am in the midst of a grant process myself currently assembling a research team and gathering their resumes. It takes patience but it's worth it.