A blog post by Arrington over at TechCrunch calls attention to the usefulness of Google's freshness filter for restricting results to recent, or older, content.

Filtering Google Results by Freshness

One of the commenters offers a 24 hours filtered google search provider for installation into your browser search box.

The cool thing about digging into advanced search or manually adding the query parameter “&as_qdr=d” to the URL, is that you then get a drop down filter for adjusting the date restriction.