I found 2 of the best answers from
I used to work in a bar cum restaurant back in melbourne. I have never question my superior on what is the difference. I only know that he show me how to make it.
Now after 8 yrs later .. I'm finally enlighten .. eureka ...
"cappuccino is a serving of espresso (about 2 ounces) with essentially similar amounts of milk and a rather stiff milk foam. Caffè latte is a serving of espresso with about three times as much milk, topped with a short head of foam. So a latte is milder and has a milkier taste." from http://www.ochef.com/87.htm
"Both a latte a cappuccino are usually based on a 30ml shot of coffee. A cappuccino is 1/3rd coffee, 1/3 warm milk and 1/3 froth (Thats when its made properly- usually alot of people will make it milkier than that). A latte is supposed to be served in a glass rather than a cup, and is 1/4 coffee, 2/4 milk and 1/4 froth. For its optimum, the beans need to be grinded just before use and the milk should be textured to 60 degrees celcius" from http://www.answerbag.com/q_view/4502