Below are links to News Feeds of various Funding Sources. You can subscribe to the Feeds, or use the link to go to the webpage where the Feed is displayed. More will be added as they become available.

Grants.gov
    New Opportunities by Agency http://www07.grants.gov/rss/GG_NewOppByAgency.xml
    New Opportunities by Category http://www07.grants.gov/rss/GG_NewOppByCategory.xml
    Modified Opp. By Agency http://www07.grants.gov/rss/GG_OppModByAgency.xml
    Modified Opp. By Category http://www07.grants.gov/rss/GG_OppModByCategory.xml

NIH Feeds http://www.nih.gov/Subscriptions.htm

HHS Feeds http://www.hhs.gov/rss/index.html

HRSA http://www.ask.hrsa.gov/HIL.xml

NSF
    http://www.nsf.gov/rss/rss_www_funding_pgm_annc_inf.xml
    http://www.nsf.gov/rss/rss_www_funding_upcoming.xml

DOD Feeds
    DARPA http://www.darpa.mil/Rss.aspx?Colid=24
    AFRL http://www.wpafb.af.mil/rss/TopStoriesByCategory.asp?catId=216
    AFOSR http://www.wpafb.af.mil/rss/
    CDMRP http://cdmrp.army.mil/pubs/press/press.shtml (webpage, not RSS)
    ONR http://twitter.com/usnavyresearch (Twitter)
    SBIR\STTR http://twitter.com/dodsbir (Twitter)

American Heart Association http://www.heart.org/idc/groups/heart-public/@wcm/@global/documents/rssfeed/t1_3.xml

American Lung Association http://www.lungusa.org/system/rss/channel.jsp?subsiteID=55336064&feed=feed-88069444&feedFormat=rss2

Howard Hughes Medical Institute http://www.hhmi.org/news/rss20.xml

Alabama EPSCoR http://alepscor.aamu.edu/reports.html#anchorNEWS (webpage, not RSS)

ScanGrants http://twitter.com/statuses/user_timeline/34763408.rss