"Romantic" is one of the great grab-bag terms of literary history. It means, for English poetry, roughly the historical period from 1798 to 1837 (between Wordsworth and Coleridge's Lyrical Ballads and the accession of Queen Victoria), but it's less a strict chronological period than a sensibility. That sensibility has so many disparate elements that we call both Wordsworth and Byron, who were polar opposites in almost every possible way, both "Romantics"--so you can see that it's not the most definite of critical terms.
A list of some elements that several "Romantic" poets share might include: an interest in personal experience and subjective emotions, an interest in everyday things and in ordinary language, an interest in heightened, altered, or morbid states, an interest in the Gothic, the medieval, the heroic (you see how contradictory these elements get--yet all of them are combined in a writer like Coleridge, for example). Perhaps the most consistent connection among Romantic poets is political radicalism. Though several of them moved to the right politically as they aged, young Romantic poets shared an irreverent, anarchic, revolutionary spirit, and were strongly engaged politically.
Romanticism was an international sensibility extending into music, art, and fiction; the English poets, however, were among the international leaders of the phenomenon.
See the Romantic Chronology at UC-Santa Barbara.
The Romantic Circles site-- an excellent, sprawling collection of resources
Another timeline: mostly musical but with good cultural landmarks
The Blake Archive is one of the best resources for the study of William Blake
Romantic Circles resources include the Byron Chronology
Here's a Coleridge Archive from the University of Virginia
A tiny biography of Ebenezer Elliott
Leigh Hunt: a picture and brief bio
Keats: a chronology; an engaging biography; a British Library site with digitized manuscript images; www.john-keats.com
A little bit about Walter Savage Landor
Thomas Moore from the Contemplator
Home page of the Thomas Love Peacock Society
Andrew Crumey's Walter Scott page
Part of the UCSB Romantic Chronology is this specialized Shelley Chronology
A brief bio of Robert Southey
A biography of Wordsworth by David Rasnake; hard to read (white on grey tiled design) but useful text