Who is Saruman in the movie?
Saruman the White is a wizard, head of the order of Gandalf the Grey. He is a very wise wizard, but he has joined with Sauron and is now breeding an army of Uruk-hai to help him in his quest for dominion. He desperately wants to get his hands on the One Ring.

Who was Saruman in the book?
Saruman the White is one of the Istari or wizards. He is the head of the White Council, and wise in the lore of the Rings of Power. He lives in the tower of Orthanc, in Isengard, where in secret he has made a pact with Sauron.

Changes in Fellowship of the Ring
Introduction at the council of Elrond
Saruman the White is first introduced to us at the council of Elrond, where Gandalf tells of the events that prevented him from meeting up with Frodo in the Shire. This tale is used in the movie as an actual scene, rather early in the movie (see 1.02.a* The Treason of Isengard). In this scene we see Gandalf arrive in Isengard to ask Saruman for advice about the Ring, but the wizards ends up rejected Saruman’s offer to join Sauron and is imprisoned on the rooftop of Orthanc where he is saved by Gwaihir.
The events in the book show the cunning mind of Saruman: there he has asked Radagast the Brown, another wizard, to contact Gandalf and tell him to come to Isengard because the Nine left Minas Morgul. Gandalf believes Radagast and travels to Isengard, where Saruman offers him to join Sauron. Gandalf refuses, and Saruman imprisons him. But Gandalf, believing what Radagast told him, had asked the other wizard to let birds and beasts look out for any sign of the enemy and Gwaihir, bringing news to Orthanc, ends up saving Gandalf.

Appearance
Tolkien describes Saruman as an old man, swathed in a great cloak, the colour of which was not easy to tell, for it changed if they moved their eyes or if he stirred. His face was long, with a high forehead, he had deep darkling eyes, hard to fathom, (…) His hair and beard were white, but strands of black still showed about his lips and ears. The great strength of Saruman was not in ‘magic’, but in his voice which was low and melodious, its very sound an enchantment. [3.X. The Voice of Saruman]
The casting of Christopher Lee as Saruman was spot on, it seems, and the make-up and whig go a long way in bringing Saruman to life.
The costume department did not heed Tolkien’s description of Saruman’s cloak though, which according to Gandalf seemed white, (…) but were woven of all colours, and if he moved they shimmered and changed hue so that the eye was bewildered. [2.II. The Council of Elrond] In stead they opted for a white gown which looks old and worn. The many colours of Saruman were quite important for his character, though, because at one point he shouts at Gandalf: White! It serves as a beginning. White cloth lay be dyed. The white page can be overwritten; and the white light can be broken. [2.II.]

A mind of metal and wheels
In his adaptation Jackson attaches a lot of importance to the environmental theme in Tolkien’s works. We can clearly see this in his portrayal of Saruman: he uses the palantír, a device which may not be safe to use according to Gandalf; he articificially breeds an army of ‘enchanced’ Uruk-hai; he lets all the trees be pulled down and used as firewood for the giant smithy that is located in the caves beneath Isengard. This is very true to the way Saruman operates in the books, where he doesn’t use ‘magic’ at all, but on the contrary uses technology as a weapon – expressing Tolkien’s dislike of this technology.
A slight change to his character in this light is the scene where he commands a great blizzard on Caradhras to stop the Fellowship. This is not like the Saruman in the books, and although one cannot exclude the possibility that Saruman is indeed behind the snow storm, this is not the option I would choose when reading the book (see also 2.03. The Ring Goes South).

The Uruk-hai
Another ‘problem’ in the movies are the Uruk-hai. In the books, the Uruk-hai are larger Orcs who seem resitant to sunlight and recieve orders from Saruman. However, we are not introduced to them until we meet up with Merry and Pippin in ‘The Two Towers’. The other Fellowship members have no idea what they are before they encounter them at Helm’s Deep. In ‘Fellowship of the Ring’ the word ‘uruks’ is mentioned only once, in relation to some large Orcs in Moria.
The character of ‘Lurtz’ was completely made up by the script writers.

Mistakes
– Saruman pronounces the name ‘Khazad-dûm’ incorrectly: both K and H should be pronounced resulting on something like ‘kh’ in stead of the Germanic ‘ch’. This is not a mistake however, because the language of the Dwarves, Khuzdul, was a well-kept secret and it is well possible that Saruman simply couldn’t pronounce it properly. The fact that Saruman knows Gandalf knows there’s a Balrog inside Moria is quite wrong, though: in the books it is made quite clear that Gandalf, nor anybody else for that matter, had any idea what it was that killed Durin and caused the Dwarves to leave Khazad-dûm.
– Just a minor complaint but the sign of the White Hand is not found on the helmets of the Uruk-hai but on their shields. On their helmets they carry the S-rune.

Bookie Details
– The palantír of Saruman is described as ‘A globe of crystal, dark, but glowing with a heart of fire.’ [3.IX.VoS]
– When the Orcs are pulling the trees in the vale down, you can hear them moan. This is not described in the books; however, Tolkien does have a very specific view on nature, in which trees are living creatures with a personality.