In the Energy Saver system preferences you will find a button labelled "Schedule." This allows you to schedule your mac to startup and shutdown at certain times, on certain days.
This is just about the only way to schedule things without buying other software or using iCal. Basically you can set your computer to come on in the morning on weekdays and go off in the evening for example.
I combine this with a locked screen saver. In the evening I start my "Big Clock" screensaver, then put my mac to sleep. In the morning it wakes up at a specified time, and loads the password dialog box. Then, when no password is typed in, it goes to the screen saver after 30 seconds. This means when I wake up in the morning I can look over and see the time in big bright letter next to me, without them on all night to wake me up.
You can also combine this with an applescript or automator actions to play music or load web pages every morning. After writing the script to do this, set a daily alarm in iCal that loads it every morning, but make sure to make it a minute later than the time your mac wakes up from sleep.