I have heard some people saying that Chancellor Palpitine becomes Emperor Palpitine (which would mean he was force-sensetive and secretly training) and that Darth Sidious becomes Emperor Palpitine. (And out of chance it is the last name of Chancellor Palpitine) Also i have heard that Chancellor Palpitine is Darth Sidious. I want to know WHO is WHO?

because some of this will probably be in ep III i will put my answer in a spoiler tag



Palpatine is Darth Sidious

according to EU, palpatine/ Sidious is self taught in the ways of the sith. apparently he stumbled upon a sith holocron.

using the sith title Darth sidious he has secretly been unhinging the republic in order to get palatine (his other alias) more power, in ep I he was made Chancellor and in ep II he got an army.
in ep III he will disband the republic and start the new order of which he will be emperor.

From my source which I have to find again it claims Sidious had a Sith Master and was trained by him and that Sidious is from the long line of Sith just waiting to take their revenge on the Jedi.

thank you both for your awnsers. i am pleased to at last know. (I wonder where Palpitine got the Sith holocron? i doubt he would have stole one from the Jedi Temple)

From StarWarsNet (http://www.starwarsnet.co.uk/askyoda.htm):

Darth Imperius' apprentice was Sidious/Palpatine. Betray and murder his master he did.


Palpatine belongs to a long line of Sith known as Bane's Order, which was started by Darth Bane after the Battle of Ruusan and emphasizes the rule of two Sith at a time, a Master and an apprentice.

Thanks wassup, SW.com only hints at it.