Next week Square-Enix is going to release Itadaki Street DS in Japan and this brief commercial gives a fair idea about how the game plays. You start by rolling a die then moving around a board with numbers on the bottom. If you land on an empty square like Mario did in his turn you can by the property (a la Monopoly) and when another player like a slime lands on the space they pay you money. Also like Monopoly you can purchase blocks of property and spend some of your money to develop your land. The real "twist" in Itadaki Street DS is the Mario meets Dragon Quest theme.
Also see: The characters in Itadaki Street DS