Here's the answer....
:salam2:
With regard to the salaam, the scholars said that it is makrooh to say the first and second salaam at the same time as your imam, but if you say the first salaam after he has said the first salaam and the second salaam after he has said the second salaam, there is nothing wrong with this, but it is better not to say the salaam until the imam has said both.
With regard to all other words of the prayer, it does not matter if you say them simultaneously with the imam, or before him, or after him. If we assume that you hear the imam reciting the tashahhud, and you have already recited it, this does not matter, because anticipating the imam in the words of prayer, apart from the first takbeer and the salaam, does not affect the prayer. Similarly it does not matter if you recite al-Faatihah before him and say Wa laa’l-daalleen “nor of those who went astray” [al-Faatihaah 1:7 – interpretation of the meaning], whilst he is still reciting Iyyaaka na’abudu wa iyyaaka nasta’een “You (Alone) we worship, and You (Alone) we ask for help (for each and everything)” [al-Faatihaah 1:7 – interpretation of the meaning], in Zuhr prayer, for example, because it is prescribed in Zuhr and ‘Asr prayer for the imam to let the people hear the verse he is reciting sometimes, as the Messenger of Allaah (peace and blessings of Allaah be upon him) used to do.
Here's the link to an entire article about how to, and not to follow the Imam
http://www.turntoislam.com/forum/showthread.php?t=3393
