What is your cron job? When I run a script from cron, I send all its output to /dev/null or to its own log file. Don't know if this is the right way to do things, but it does keep those emails from flooding my box.
For instance, let's say I cron up2date on my servers. I'll write the cron script like this:
If you want to keep track of the activity your script is generating, then you can just do something like this:
/usr/sbin/up2date -u > /dev/null
Don't know if this is the right way to do things, but it has so far worked for me.
/usr/sbin/up2date -u >> /var/log/my_cron_log