What is the correct way to recite Darood Sharif - Durood e Ibrahim?

I have been listening Darood Sharif on youtube and I have notice reciter say Muhammadin and other reciter say Muhammad. Also reciters say Ibraheem and Ibraheema. So for example: Reciter One: http://www.youtube.com/watch?v=WW8gxrrT2tY > Allah humma sal-li 'ala Muhammad**in** > wa 'ala ali Muhammad**in**, > Kama sal-layta 'ala Ibrahee**ma** > Wa'ala ali Ibrahee**ma** > innaka Hameedum Majeed Reciter Two: http://www.youtube.com/watch?v=kBkmAapKkpE > Allah humma sal-li 'ala Muhammad**in** > wa 'ala ali Muhammad, > Kama sal-layta 'ala Ibraheem > Wa'ala ali Ibraheema > innaka Hameedum Majeed So which is the correct way to recite Darood Sharif - Durood e Ibrahim when praying salaat?