Hi,
I have used Lightroom 2 to select and edit my pictures and then save it with a smaller file size into my Photo Folder in iphoto. This will allow iphoto to import the picture. This workflow allows me to incoporate the use of iphoto's slideshow which I like as a mean to showcase my pictures.
As for creating a book, once the pictures are inside your iphoto folder, it should be straight forward.