SEGN interviewed Julia Jones who is playing the Leah in Eclipse. There is an audio interview and a partial transcript.
On reading the books: “I got very obsessive and went through all 4 of them. In the last week and a half, I’ve read the first 3. I just finished Eclipse today. I think the books are incredible. Stephenie Mayer[sic] managed to capture a level of humanity, especially with Bella’s character. Her inner thoughts are the similar thoughts you’ve ha d in similar situations but they’re so deep down, ones that you sometimes don’t even admit to yourself.”