New to Arduio! Timer help!

If someone could help with writing code to do the following:

Hold a button down for 15 seconds and a buzzer sounds for 30 seconds and at the end of the 30 seconds, the buzzer ends unless the button was held down for 10 seconds to "disable" the buzzer.

Any help would be great! Thanks a bunch!

for a start look at the "blink without delay" example

http://www.arduino.cc/en/Tutorial/BlinkWithoutDelay

in a nutshell you make a timestamp, and every loop check the current time vs the old time, if the difference is greater than your predetermined amount, bob's your uncle