General
National Invasive Species Information Center
http://www.invasivespeciesinfo.gov/
National Biological Information Infrastructure Invasive Species Information Node
http://invasivespecies.nbii.gov/
TNC The Global Invasive Species Team
http://tncinvasives.ucdavis.edu/
National Institute of Invasive Species Science
http://www.niiss.org/cwis438/websites/niiss/home.php?WebSiteID=1
National Invasive Species Council
http://www.invasivespecies.gov/
RMRS Wildlife and Terrestrial Ecosystems - Ecology and Management of Invasive Species
http://www.rmrs.nau.edu/wildlife/invasives/
Aquatic Species
USGS Nonindigenous Aquatic Species (NAS) information resource
http://nas.er.usgs.gov/
National Exotic Marine and Estuarine Species Information System
http://invasions.si.edu/nemesis/
Aquatic Invasions Research Directory
http://invasions.si.edu/aird/
Plants
USDA NRCS Plants Database - Invasive and Noxious Weed List
http://plants.usda.gov/java/noxiousDriver
University of Mmontana Invaders Database
http://invader.dbs.umt.edu/
Center for Invasive Plant Management
http://www.weedcenter.org/
Pathogens
USGS NationalWildlife Health Center - Invasive Pathogens and Emerging Diseases of Wildlife in the United States-
http://www.nwhc.usgs.gov/our_research/invasive_pathogens_ and_emerging_diseases_of_wildlife_in_the_united_states.jsp
Invasive Pathogens Laboratory
http://www.esr.cri.nz/competencies/communicabledisease/Pages/IPL.aspx