Google's planning to host your printer drivers in its cloud to make the Chrome OS (debuting today) a viable option. Now there's a landing page where you can test Google's web-based printing, if you're using the latest Chrome dev release on Windows.
Google's Cloud Print page, which carries the beta tag, walks you through the process of setting up cloud printing in the latest version of Chrome — it's a setting in the Under the Hood section, where you'll register with your Google credentials.
Having set that up and synced your local computer's printer drivers, you'll be all set to print from any computer that's also running Chrome, or (presumably) Chrome OS or some future mobile app, assuming that same computer is connected and ready to print.
I tried out Cloud Print this morning, and it was able to recognise all my printer drivers — including the doPDF print-to-PDF app — and print out a test page, the top portion of which is pictured at the top of this post. It's a promising peek at Chrome OS, which seems slated to debut today.