The BamZ Interactive Insoles (from $14) will let you program messages of up to 40 characters long. The message is then displayed at the back of the shoe as you walk along. The insoles are cut to size to fit any type of shoe.
BamZ are the latest in innovations and are a lifestyle product. BamZ allows the wearer to individually express themselves using pressure pads within an interactive insole. The first BamZ allow a completely programmable message of up to 40 characters to be displayed at the back of the shoe. So when the wearer walks, the pressure pads within the insole switch on the personally programmed message which is displayed on the outside.
(Via Shiny Shiny)