PoetsPoets.org is affiliated with the Academy of American Poets. At first glance, it seems a little less welcoming than the two sites mentioned already, but when I started digging in its resources are great, not least the very cool regional map of the USA, including bios of key poets, poetry events, poetry-friendly bookstores, and poetry history. The Academy of American Poets inaugurated National Poetry Month so, unsurprisingly, they're also a great resource for that as well.