Skaters commonly wearing special kind of shoes. However, from my point of view they just look like a pair of sneakers.
In most cases these are very expensive and I asked myself if they're really necessary equipment? Or is it just for "identification"?
I've only skateboarded much when I was younger, and have only about an hour of practice total this past year, but here is what I know:
There are a few things that make a skate shoe good for skateboarding.
The sole is very flat, and typically grippy, so it adheres well to the skateboard. The shoe's body is typically cushy, to protect your foot if you land awkwardly or hit the side or top of your food with the board while flipping it.
A (good) skateboarding shoe also needs to be reinforced, because skateboarding will destroy the shoe pretty quickly otherwise. The top part of the skateboard is covered in grip tape, which is not unlike shingles, so you can imagine it's very gritty. To do one of the most basic tricks, the kickflip, you have to slide the side of your shoe up the skateboard, on the grip tape. If the side of the shoe is not reinforced, it's going to get destroyed fast. I personally had some very nice "slip ons" canvas shoes, and they got pretty badly torn up right above the pinky toe from about 15 minutes of kickflip practice.
That said, they are not required, and if your regular sneaker has the characteristics above, it should be fine to skate in. The rest is personnal preference; color, style, weight, balance, signature shoe, etc.
For further reading:
Skateboard.about.com on what is a good skate shoe.
The Ride Channel things you didn't know about skate shoes.
