I've seen Star Wars more times than I've seen Harry Potter so I didn't need to refamiliarise myself with them to notice the obvious similarities this time round. For those who are a little slow on the uptake here's the gist of things. The first two Harry Potter films/books are almost irrelevant, they're like a prologue. Prisoner of Azkaban is Phantom Menace, Goblet of Fire is Attack of the Clones, Order of the Phoenix is Revenge of the Sith, The Half Blood Prince is A New Hope, and the last book; Deathly Hallows, is split into two; Empire Strikes Back and Return of the Jedi.
Even further than that, the individual characters are highly comparable, Harry is Luke, Ron is Han, Hermione is Leia, Dumbledore is Obi Wan Kenobi, Snape is Vader, Voldemort is Sidious heck even Hagrid is Chewie, they're both big and hairy for Christ's sake.
But like I say this isn't necessarily a bad thing and it certainly doesn't undermine Rowling's books. In-fact—and this is news—I actually prefer Rowling's telling of the Story to Lucas's, because—SPOILER SPACE BEGINS—Harry and Voldemort's Relationship is more significant than Luke and Sidious'. And also because some of the stuff Sidious does seems to be a little bit of an accident, whereas Voldemort's plan was way more sophisticated. I mean sure it's impressive that Sidious hid in plain sight of the Jedi for a very long time, and also managed to turn the greatest Jedi of all time to his cause. However, Voldemort, made a Horcrux of the one person who he knew the good guys wouldn't kill because he was the one prophesised to destroy him. Genius, absolute genius, he forgot one thing though, Magic, which to be honest is a bit of an epic fail in the Harry Potter world. SPOILER SPACE ENDS
So there you have it, my two cents/pennies. Unfortunately if you skipped over the spoiler parts this post won't be entirely interesting to you so read the books and then read this.