Modo is a clothing store located in East Holland, Algonquin in GTA IV. It is a nice place to buy sportswear. Like many other stores in GTA, It can be robbed. There are two ways to rob it.
WAY 1: Go to Modo and walk inside. Draw your pistol and shoot the cashier before he can leave. An alarm will activate, so quickly walk up to the cash register and press the "Pick Up" button to open the register. There is usually $50-$200 dollars in the register.
WAY 2: Go to Modo and walk inside. Go behind the register. Probably the game will automatically push the cashier aside, which he doesn't mind. Rob the register with the "Pick Up" button. By now, he probably got up. Let him run away or shoot him down to be extra violent!
gta4onlineguide.com - has pictures and prices for all the clothing in Modo