For Win 2K/XP users only.
Serverloader does not yet have a built in task schedular, so until one shows up you can use the windows schedule service to run command files (batch or script files) which can control the stopping and starting of HLDS as well as any other process loaded by the serverloader.
For example, you can have a Natural Selection server running during the day, and a Counter-Strike server running at night. You can have bots all week, but none on weekends.
Go here to get started.
Windows 2000 Task Scheduler
There's other resources on the net if you search for them. Personally I prefer the "AT" command line interface, but I'm old school.