E Learn English Language provides a chart explaining the mechanics of the simple present tense of the English language. Easy Space Learning has several different educational charts encompassing the 12 verb tenses of the English language
Only two simple present conjugations exist in the English language for all verbs except the verb "be," which has three conjugations, and modal verbs, which have no conjugations. English the Easy Way has charts of the English simple present tense as well as charts of the English present perfect tense. The site also provides information on the differences in usage of the two tenses.