cronjob + sed

Hi

How do you set up cronjobs with cygwin? If I want to run a script that uses sed ( does thet standard sed that comes with cygwin supports /s /g etc commands to manipulate a string or do I need to upgrade sed? )
and gets an input file  from a windows directory and output a new file on that directory?
Tried to look for crontab  but couldn't find.
Thanks