Does anyone know of a way to configure the iPhone to only use the e-mail push setting (for Exchange) during specific hours of the day? I want to leave my ringer on at night but prevent it from making noise when an e-mail comes in.

I know that I can just set it so there is no sound when e-mail comes in...but that requires remembering to do it every night. This is something that was built into Windows Mobile...just wondering if maybe a CRON entry could do it?