I wrote a python script to monitor a log file on a CentOS server for a specific value and send an email when it finds it.  It runs as a cron every 5 minutes.
My question is what is the best way to put this script to sleep after it has sent the first email.  I don't want it to be sending emails every 5 mins, but it needs to wake up and check the log again after an hour or so.  This is assuming the problem can be fixed in under an hour.  The people who are receiving the email don't have shell access to disable the cron.
I thought about sleep but I'm not sure if cron will try to run the script again if another process is active (sleeping).
You are running it every five minutes. Why would you sleep it? Just exit. If you want to make sure it doesn't send email every five minutes, then make the program only send an email if there is anything to send. 
If you sleep it for an hour, and run it every five minutes, after an hour you'll have 12 copies running (and twelve emails sent) so that's clearly not the way to go forward. :-)
How to sleep a python script running as a cronjob?