Even though newer Operating Systems have the ability to automatically switch the ringer to vibrate or off when set to automatic, there is no real native option to schedule profile switches.

TProfiler is a simple and free application that can be used to schedule up to four events occuring on certain days at certain times when your device will automatically switch to another notification mode. You can choose between sounds on, sounds off and vibrate. We wish it could be able to set the volume of notifications but this being a beta version, we might see that in future releases. Currently it has been tested on the HTC HD2 and Touch Pro2, but it should work on other WVGA devices too.

(Source: XDA Developers)