All the SketchUp video tutorials can be viewed online at the SketchUpVideo YouTube channel.
If you're having trouble viewing these videos on YouTube, they're now available for download. You can get the ZIP files at the SketchUp Videos site.
After downloading a video, double-click the ZIP file to extract the MOV file, which is the video. MOV files are best viewed with Quicktime. Please visit Apple's Quicktime page to download Quicktime if you don't have it installed.