I set my podcasts to update every hour. This applies to all podcasts; iTunes lacks an option to update just one podcast hourly, and there doesn't seem to be an AppleScript command to update them programmatically. I then modified this hint, which inserts a song into the Party Shuffle list, to insert the newest CNN update into the Party Shuffle if and only if iTunes is playing from that playlist. Here's the modified script. I saved this as ~/Documents/cnn-update.scpt. I then used cron to run this script at the top of every hour:
$ cat > /tmp/entries
0 * * * * osascript /Users/jweill/Documents/cnn-update.scpt
^D (control-D)
$ crontab /tmp/entries
The only downside is that I usually get an e-mail locally that contains some text like "iTunes, iTunes, iTunes, iTunes," or a status message, when the script gets run. I don't know how to suppress that output without just adding > /dev/null to the command in crontab.

