The following sites provide more specialized information relating to preparing an application for the National Science Foundation or the National Insitutes of Health:
A Guide for Proposal Writing - The National Science Foundation http://www.nsf.gov/pubsys/ods/getpub.cfm?nsf04016
(This Guide was specifically prepared for programs in the Division of Undergraduate Education.)
Grant Writing Tips Sheets - Office of Extramural Research, National Institutes of Health http://grants.nih.gov/grants/grant_tips.htm (This site focuses on research proposal preparation.)