I'm looking for the best way to import a feed, say BBC News, and filter through all the content so only articles containing a keyword are stored in the database. I'd like each item to be shown as a node of a specific content type and for it to be updated every given time interval. Is there a straightforward way to do this? I don't have much experience in PHP at all, so please be specific.
The friendliest UI driven way to do this is probably with the Feeds module. Make your content type(s) using Drupal Fields and use Feeds to ingest the content via Cron or job_scheduler module. You might still need to code a simple module to do some things ... but it would require little coding I think.
The less friendly way would be the Migrate module (has a status-indicator UI, but no helpful UI for creating/moving fields). You'd end up coding alot of php to rip through XML and create X nodes in some content type. But, you'd still get a way to import/update/rollback items from RSS. They do have XML "News" examples I think in the Migrate modules example folder in the project.
I'd go with Feeds if you're new to this and stumble your way through that ... I haven't used it. I can only recommend it.