Try Wordpress with WP-O-Matic or reFeed. Both preform that funtion. WP-O-Matic can be run as a cron to do the updating and reFeed would require you to have it pull the feed via a button (in lack of a better word) import from inside the admin area of Wordpress.
I myself like the reFeed option which gives you more editoral control over the content to add adsense code. I've have setup the WP-O-Matic on other sites for people who didn't want to fool with the site too much.