I read this back in 2004 and remember being captivated by the storyline - such a good premise! The film was awful though, and it's a shame they couldn't stick to the original location of the book.
I re-read PS I Love You last year and wasn't as fond as I was before, perhaps due to the film ruining it slightly, or because I had read it before. I'd give it a 6.5/10.