I don't have much to say about this chapter, and in many ways it stands as a last calm before the storm. There's conflict, but as far as conflict goes, a rather minor one, and one that results in Frodo gaining free passage through Gondor.
Beyond the location within a secret cave, I don't get the inviolate nature of the pool that Gollum fishes in. But that's the way it is, and Gollum becomes the elephant in the room. While Frodo saved his life, this whole encounter probably marks the sharpest change in Gollum's overall attitude towards the hobbits. When Frodo comes upon him, Gollum is muttering about how he was left behind as the Master went off with new friends, then only to be tricked by the Master and taken captive by men.
Things are a bit more serious and weighty in the film, with Frodo caught flat out in a lie, rather than just omission. This forbidden pool is right out in the open, so I'm pretty sure all sorts of beings end up in it. The betrayal of Smeagol comes across with more brutality, a harsher breaking of trust, and the playing out of the Gollum/Smeagol personalities makes the injury and turn even more stark.
This Faramir is less... nobly pure as the one in the text. But it severs the mood of this scene well. He does not take the Ring, but he knows it's power and in this case follows the law by insisting the Ring goes to Gondor. In the scope of the movie though, it really just seems like an excuse to show another battle scene... and maybe to give Frodo a creepy child moment of "they're here." Actually, I take that back, Jackson has cut things so we have two parallel fights against the forces of darkness going on. Cinematically it gives a balance, but drags things out a bit.