Use Firefox and get the addon "DownloadHelper" This will let you download just about any embedded video file on a website. Be it FLV, MP4, etc.
I would suggest DownloadHelper for Firefox as well, it supports Google Video http://www.downloadhelper.net/
You can also use JDownloader if you dont want the Videos in .flv-format. It converts them automaticly to .mp4 or you can extract the audio to .mp3. For only downloading .flv the DownloadHelper is the best choice.
I use download helper to download them then I use free video converter by koyotesoft to convert them to any format I want or if you want to make them DPGs use Batch DPG