Click on the following links to practice/compare the different tenses listed on the right.

Verb Tense Exercise 5 Simple Past and Present Perfect
Verb Tense Exercise 6 Simple Past and Present Perfect
Verb Tense Exercise 7 Present Perfect and Present Perfect Continuous
Verb Tense Exercise 8 Present Perfect and Present Perfect Continuous

Verb Tense Exercise 9 Present Continuous and Present Perfect Continuous

Verb Tense Exercise 10 Present Continuous and Present Perfect Continuous

 Verb Tense Exercise 11 Simple Past and Past Perfect
Verb Tense Exercise 12 Simple Past, Present Perfect and Past Perfect

Verb Tense Exercise 13 Past Perfect and Past Perfect Continuous
Verb Tense Exercise 14 Present Perfect, Past Perfect, Present Perfect Continuous and Past Perfect Continuous
Verb Tense Exercise 16 Present and Past Tenses with Non-Continuous Verbs
Verb Tense Exercise 17 Present and Past Tense Review
Verb Tense Practice Test Cumulative Verb Tense Review
Verb Tense Final Test Cumulative Verb Tense Review

http://www.james.rtsq.qc.ca/Virtgram/pasperf.htm simple practice of identifying the correct form of
past perfect tense

http://www.englishpage.com/verbpage/presentperfect.html explains and has exercises

http://www.paccd.cc.ca.us/instadmn/engfl/esl/study.html

  scroll down to 'perfect tense' on this site. On the links here, most of the questions you have to just think of the answer. You cannot type it in. The correct answer is shown with the drop-down arrow

http://www.accd.edu/nvc/areas/esol/grammar.html gives explanation and practice for all tenses

in English