QuoteCron Service for Windows. Allows you to use the Unix crontab file format to schedule processes. Runs as a service that works on Windows 2003, XP, Vista, Windows 7, Windows 2008, 64 bit and 32 bit versions of Windows
I use this tool at work and it's more functional compared to the old versions of MS scheduler service.
The site is providing other nice tools like Remote Execute, RDP Detect, VNC Password tools :
http://www.intelliadmin.com/index.php/downloads/
Thank you for that good link, Vortex.
Gunther
Another tool :
Freebyte Task Scheduler (http://www.freebyte.com/fbtaskscheduler)