In the Myths of innovation Scott Berkun analysis the what works and doesn't work in creating innovative products.
He looks at the Myths that surround innovation and breaks the process down to a pragmatic guide to creating the space to be a more productive innovator. Written in a relaxed style you'll plough though the book in no time at all, and come away inspired.
Anyone who wants to go further in software/product/web design should read this book.
Also, don't forget to read the Colophon as with all of Scott's writing it's a treat.