I'm a fan of the Star Wars films.and Star Wars in general but I never got into the comics or any other Star Wars media, so I know nothing more that what i have seen in the films.
  
So I was reading a star wars wiki about  Palpatine on how he became a sith, how he trained Darth Maul etc.... Then I came across the part in the article on how he died, because I knew how he died because I'd seen it it the film I skip that section and started to read on.
 
This is were my question starts, It said Palpatine was reborn and became a clone, is that even possible? Does that mean the empire came back? This kind of makes Return of the Jedi a pointless film.
 
Sorry about all the movie question but I was hopping they explained all this in the comic books?

Here's what happened:
 
Palpatine's first recorded death was on the second Death Star. He used a power called "Transfer Essence" which he used to escape his body. He traveled to Byss where he had clone bodies; he then took possession of them. But the clone bodies were incapable of sustaining his vast power, and so they started to wither and die. He set his sights on the newborn Anakin Solo. He was finally killed when a Jedi allowed Palpatine to possess him, basically killing himself so Palpatine could not return.
 
These events occur in Dark Empire, Dark Empire II, and Empire's end. Now the whole Empire thing is a different question altogether.

The Empire was basically scattered after the Battle of Endor, but it wasn't completely destroyed. There were still surviving commanders that vied for control. One such was Grand Admiral Thrawn, who was close to bringing the Empire back - but he was killed. Palpatine, soon after, also attempted to bring it back - I already explained what happened after that. All this time the Empire was called the Imperial Remnant for there was no true Empire - just different factions. One faction was controlled by Jerec, a Dark Jedi that wanted control of the Valley of the Jedi. Desann - another Dark Jedi - tried the same, but ultimately failed. Tavion, Desann's apprentice, attempted to bring back the fallen Sith Lord Marka Ragnos, but was stopped by Jedi Knight Jaden Korr. Eventually, after the Yuuzhan Vong War (which the Empire participated in), the Imperial Remnant was starting to unify, making their main homeworld Bastion. They were on "good terms" with the Galactic Alliance (the New Republic was destroyed during the war. The Galactic Alliance was made up of the remaining members of the New Republic). I'd mention their role in the Second Galactic Civil War, but it's rather complex and has less to do with the Imperial Remnant as it does the Galactic Alliance.  Everything I just mentioned took place over a span of 35 years.
Many years later - around 80, actually - the Empire had unified under the new monarchy. The emperor, Roan Fel (the guy I have as my avatar, for the record) was coaxed into attacking the Alliance while it was weak, but he didn't put all of his effort into the war - not even allowing his Imperial Knights (basically Grey Jedi who have a loyalty to the Emperor and are trained to put the Empire's interests first. They're not Sith, however. They serve the light). The New Sith Order eventually allied themselves with the Empire. Fel was against their alliance, but the Moff Council overruled him. Flash forward and the Sith brutally attacked the Jedi homeworld of Ossus, the Empire took control of Coruscant, and the Alliance was basically destroyed and the Jedi in hiding. The Sith turned against the Empire, with their leader Darth Krayt taking the throne from Roan Fel. Fel and his Knights retreated to Bastion where those still loyal to him - not the throne - gathered their forces. Thus the Sith-Imperial War began.
 
I may have missed some details - intentionally, for the sake of simplicity, or because I may have forgotten. For more information, go to Wookieepedia.