Search for Funding
http://www.grants.gov/: Search all federally-funded grant and fellowship opportunities
http://www.cos.com/: Search both federal and private grant and fellowship opportunities
www.cdc.gov/od/pgo/funding/FOAs.htm: Centers for Disease Control and Prevention
http://grants.nih.gov/grants/guide/index.html: National Institutes of Health
https://www.samhsa.gov/: SAMHSA (Substance Abuse and Mental Health Services Administration)
http://www.hsrd.research.va.gov/: Veteran's Affairs
www.hrsa.gov/: Health Resources and Services Administration
How to find out if something's already been funded by the NIH:
NIH RePORTER (Formerly known as CRISP): http://projectreporter.nih.gov/reporter.cfm