Fiqh-Us-Sunnah, Vol 2, #34.
Abu Bakr (r) reports: “I heard the Prophet sallallahu alehi wasallam saying:
‘Allah forgives the man who commits a sin (then feels ashamed), purifies
himself, offers a prayer and seeks His forgiveness.’ Then he recited the
‘ayyah: ‘And those who, when they do an evil thing or wrong themselves,
remember Allah and implore forgiveness for their sins – and who can forgive
sins except Allah? – and will not knowingly repeat (the wrong) they did. The
reward of such will be forgiveness from their Lord, and gardens underneath
which rivers flow, wherein they will abide forever- a bountiful reward for
workers.”‘ [al-‘lmran: 135-136]. This is related by Abu Dawud, an-Nasa’i, Ibn
Majah, al-Baihaqi, and at-Tirmidhi who calls it hasan.
At-Tabarani records in al-Mu’jam al-Kabir, with a hasan chain, from Abu
ad-Darda’ that the Prophet sallallahu alehi wasallam said: “Whoever makes
wudu’ and perfects the wudu’ and then stands and prays two rak’at or four
rak’at, obligatory or non-obligatory, and perfects therein his ruku’ and sujjud
and then asks for Allah’s forgiveness, he will be forgiven.“
The Islamic Workplace 
silentarts
February 24, 2012
How do you perform this prayer?
Rafik
March 5, 2012
The answer is in the post. Look at the second paragraph. You perform two or four rakaat Sunnah or Fard, and then ask for tauba (forgiveness), then that is considered salat ut Taubah. Please note that you can make double or more nyat when you pray. For instance, let us say you intend to pray two rakat Sunnah for Fajr, you can simultaneously make the nyat that you are praying two rakat salat ut Taubah. You will get rewards for both simultaneously, but you must have the intention in your heart for both Before you begin the two rakaat.