Google realizes the need to filter search results by date. Mashable today includes a Google Search video which highlights the new Google search options. Basically, if you search for "D70 camera" in Google, you will find a text link called "show options" on the results page. Click on that link and a left hand side nav appears with (amongst other) date filters.
No doubt Twitter search pushed the release of these features. You can still use my previous filter advice which I wrote about here (paste "&as_qdr=d" at end of results URL), which will automatically filter by most recent posts within a 24 hour period.