Padraic Brady has put together a very comprehensive post on his blog today about using the Zend_Feed component of the Zend Framework to help with the aggregation of content from other sites (like RSS and Atom feeds).

In this entry I explore Zend_Feed from the perspective of someone aggregating RSS and Atom feeds with a view to building a database of uniquely identified content for later presentation in a "Planet" style application. [...] In fact all we create here is a simple command line script to aggregate content frequently (e.g. just set up cron to run it every hour or so) into a database for later presentation.

He guides you through each step of the way:

• Setting Up Database And Models
• The Aggregator Script Foundation
• Using Zend_Feed to get common data for RSS/Atom entries
• Putting It All Together

There's plenty of code (and SQL to insert) in the post and he explains each point well, helping to make the development process smoother. There's even a summary section to toss in a few extra bits of information just in case you missed them along the way.