This morning's addition of a YouTube layer to Google Earth added a whole new dimension of utility to the popular mapping application, but if you're looking to take advantage of some of that geo-tagged video goodness without installing anything, there's Mappeo. This Portugual-based site offers up nearly the same thing as Google Earth, with the addition of a search tool that lets you limit the videos to a specific area by keyword. Admittedly the service falls a little flat when you compare it to the catalog of video clips you're getting with Google Earth. There's simply not as many.
The service works in a similar fashion to the Google Earth layer. You can watch a video in a tiny embed on the map, or click on it to jump right to the video's page on YouTube. You can also skip to the next or previous video around it using keyboard shortcuts.
Expect YouTube to come up with something similar shortly. In fact, I wouldn't be surprised if they've already got a more filled out version that matches the quantity seen in Google Earth cooking somewhere in their labs.