PWM Mega 2560

I need help! I need to send a 5KHZ pulse every minute or so. Start a timer after pulse is sent then interrupt the timer by receiving the pulse via microphone. Send this value "time" to a pin as an output. Any help would be great as I'm way behind on this project!
Thanks, Dustin

Sure I'll help you out.
When do you need it by? (est is where i'm at)