Regular and Irregular Verbs
Irregular verbs can cause a lot of problems. Here are some resources for learning and correctly using irregular verbs.
Englishpage.com provides a dictionary of 370 common irregular English verbs, with past and past participle forms as well as links to definitions of each word.
This game at Quia.com will help you practice past tense forms of irregular English verbs.
The OWL Online Writing Lab at Purdue University provides a list of irregular verbs in different tenses. At the bottom of the page, there is information on common irregular verb errors.
The Georgia State University provides another list of irregular verbs and how to conjugate them in different tenses.