If you look at the link given in post #3, you will find details of how he bounces his flash. I have tried this and it is very effective.
Basically, you need a piece of black art-foam, cut to about 8"x6" and attached to your flash with elastic (as Neil does) or a velcro cable-tie (which I use). You can get this from art or craft shops such as Hobbycraft - comes in A4 size and is very cheap. Place this on the side of your flash that faces your subject to flag light from hitting them directly. The flash will then bounce off the wall, which is, in effect, your softbox.
Regarding shadows on the wall, perhaps the subject is too close to the wall.