Tasbihat al-Arba'h

If we are praying a three or four Rak'at Salat, then after reciting the Tashahud in the second Rak'at, we immediately stand up and recite the Tasbihat al-Arba'h three times:

سُبْحَانَ اللهِ وَ الْحَمْدُ لِلّهِ وَ لاَ إلهَ إلاَّ اللهُ وَ اللهُ أكْبَرُ

Subhaanal-laahi wal-hamdu lil-laahi wa laa illaha illal-laahu wal-laahu Akbar 
(Glory be to Allah and praise be to Allah and there is no god except Allah and Allah is Greater than anything else)

We then go into Ruku' followed by Sajdah, and after performing the two Sajdahs, we recite the Tashahhud and Salam. If we are reading a four Rak'at Salat, then we read one more Rak'at just as the third Rak'at and finish off the Salat with the Tashhahud and Salam.