Oh, come on - go into detail! Some of us are being 'good' (against our will!) and won't be getting the extended version right away. And I'd trust a true fan's review much more than a so-called "real" review.
Ok, I’ll spill a little of the beans. Nothing is different until Isildur gets ambushed by the orcs. When that happens he gets off his horse and puts the Ring on his finger. He disappears and you “see” the invisible Isildur (Just like you “saw” the invisible Frodo escaping from Boromir) head towards the river. He splashes into the river and the view switches to looking upwards from the river bottom. You see a confused Isildur because the Ring took that opportunity to slip from his finger, and you see it sinking away from Isildur. Isildur then gets filled with arrows and you see him floating down the river.
The whole opening Shire sequence is different. I like it a lot.
The one thing I didn’t like was how PJ made Aragorn question his destiny even more. At one point he says he never desired to be king. I don’t think the book Aragorn was that way, but it is a change I can live with.