They look like this:

Basically they're like an expensive pair of plimsoles. It takes a bit of getting used to wearing a pair of Merrell's Barefoot shoes and they take around a week to 'bed in'. Initially they're very tight, particularly if you have wide feed, and it's advisable to order at least the next half size up from your regular size.
But once they're worn in, they are extremely light and the 'Barefoot' principle really comes through. You can feel the ground through the thin (but very tough) soles. They change the way you walk and are predominantly walking shoes.
However, I purchased a pair for driving and they are very, very good. Due to the lack of a heel and the thin soles, I had to move my seat forward a touch. You can control the pedals a lot more finely and this really contributes to the driving experience.
Highly recommended!
Is anyone else into driving shoes? If so, which makes do you recommend and how have they helped your driving?