While I used an Android phone (Droid 3) at my previous job, I toyed with a number of scheduling or location aware apps to change the settings on my phone automatically. Over the past month, there have been a few released that I would enjoy testing out. Since my personal phone is an iPhone 4, I'll just have to wait. But I'll share the information so that those of you out there may be able to enjoy the simplicity that automation can bring.
WiFi Timer for Android
If you have a regular or semi-regular schedule where you are in and out of wifi areas and would like to maximize your battery life, this app may be for you. From the screenshots, this appears to be quite simple to setup. You can find more information over at redmondpie.
There are times daily and weekly that I set my phone to vibrate only. With this being a regular occurrence, scheduling it would save all the problems that arise if I actually forget to change the setting. This is where Silent Time! could save the day. Much like WiFi Timer above, it appears you can automate your regularly scheduled silent/vibrate times. You can find more information over at redmondpie.
Llama for Android
If you have more complex scheduling needs, especially ones that are location based, this app may be for you. This lets you setup custom profiles to be triggered based on Location (GPS), WiFi connection, Date, Time and possibly other triggers. You can find more information over at redmondpie.