It depends on when you signed up. There has been several variations of the cancellation fee in the past 2 years...
#1 $240 or $10 in each month remaining
#2 $300 or $12.50 in each month remaining
#4 $360 or $15 for each month remaining
#5 $420 or $17.50 for each month remaining (Took Effect 2/1/2010)
Im not sure of the exact dates on the other cancellation fees,but ever since the attorney general has been in Dish networks ass they have raised it to help some of the other losses in revenue such as the 10 day notice they must send out before they charge your credit card. It kind of sucks for Dish where as before they hit the card immediatly, and with the notice they send you, its an alert for you to cancel the card.