Hi srix,

Go into the Ideabook you'd like to move photos from. Then select "edit" right below the title, up in the top left corner. Then select the photos you would like to move and select "Move Photos To..." which is to the right of the green button that says "Done." Then you have the option of moving your photos to an existing Ideabook or creating a new one altogether. Should look like this:

Hope that helps. :)