On the Droid X, in settings, you can go to Battery Manager and set your profiles to have data be off for a specified time frame (off peak hours that you designate). Doesn't work if the X is charging, at least in the Smart Mode.
If you're looking to just silence the things you want silenced for certain periods of time, check out Timeriffic (free in the market). It's highly customizable and works very, very well.