Source: http://www.labnol.org/internet/tools/download-multiple-youtube-videos-single-movie-mp3/3406/
While there are tons of tools that let you download web videos with ease, MovAVI offers one unique feature - it can join multiple videos from YouTube, Metacafe, Break.com, etc. into one single file all by itself that you can later download in any format.
Related Reading: How to do Everything with YouTube
Using Movavi is simple - just add the different video URLs (5 is the limit) and select an output format. You can either request the combined video clip as an MP3 audio file (great for music videos) or in regular formats like iPod MP4, AVI, Flash Video & Quicktime.
Movavi will not join your videos instantly - it sends out an email when the video to ready for download. If you are looking for instant conversion, check this Flash Video Guide. MovAVI can also be used to join video files that reside on your local hard drive.
MovAVI.com [Online Video Converter]
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