Symbaloo! It is basically a way to organize and create an online "desktop" for your students. You add sites to the desktop (Symbaloo calls it a gallery), and an icon and title appear for your students. You can create different desktops for different units, subjects, themes, etc. Here is an example of a Starfall Symbaloo Gallery:
One with E-books:
If you haven't heard of Symbaloo, check it out! And blog hop over to see other techno tips today!