Your best Federal grant application  information resource is Grants.gov.

Grants.gov allows you to electronically find and apply for competitive grant opportunities from all Federal grant-making agencies. Grants.gov is the access point for more than 900 grant programs offered by the 26 Federal grant-making agencies.

Start at Get Registered and be sure to visit  Applicant Help, where you will find Frequently Asked Questions and the Applicant User's Guide.