American Literary Societies:
The Academy of American Poets: This website contains a list of national exhibits, information on hundreds of poets, a calendar of events, and updates concerning various awards and programs.
The Poetry Society of America: Founded in 1910, this society's website contains useful links, grant information, and updates.
Poets' House: A 35,000 volume reference poetry library open to the public. Poets' House also runs readings, lectures, and a public library program.
Museum of American Poetics: The Museum features various exhibits, including the American Poet Greats Lecture Series, and the Best Minds Reading Series.
British Literary Societies:
The Poetry Library: The most comprehensive collection of modern poetry containing all 20th century work published in the UK, a very wide selection from other English-speaking countries and an unrivalled collection of translations.
Poetry London: The definitive guide to poetry listings around London and outside London, including poems, reviews, features, courses, international and ethnic resources.
League of Canadian Poets: Canada's national organization for poets. It contains an extensive annotated links page, a list of Canadian poets, and a calendar of readings across Canada.
The Poetry Society: Established in 1909, and now one of Britain's most dynamic arts organizations, the Poetry Society is a membership organization open to all. Poetry Review is their house magazine, and its website can be found here.