Robert Kempinski (author of Introduction to Bonsai) has an excellent article at Knowledge of Bonsai on Shohin Willow Leaf Ficus (the photo above was borrowed from the article). Check it and a slew of other good stuff out, including a revealing exposé on nasty (but beautifully photographed) little aphids by Heather Hartman.
While you are at it, take a look at two related books we offer: Shohin Bonsai by Morten Albek (Stone Lantern Publishing), and Ficus: The Exotic Bonsai by Jerry Meislik (Devonshire Gardens Ltd.).