You can use Any Video Converter to reduce the video frame size, simply unfold"Video Option" and you can set the frame size was you wish. If you want to convert video, it is also available.
I think FLV worlks the best. YouTube videos gets converted to FLV when you upload them. When you download the videos, they always come in FLV files.
The best way to convert FLV to AVI is to use software program
Nero 10 is a dvd burning freeware, it can convert a flv file to dvd eaily.
An FLV video file is an extension of Flash software made by Adobe Systems. If an FLV file needs to be converted into a different file format so that it can be viewed, there are various free or shareware programs that will allow the user to convert the file.
File compression
http://www.xfutureblog.com/2007/09/27/how-to-reduce-or-compress-avi-file-size-and-upload-to-youtube/
File Compression
It is called Compress.
I use Online Video Converter. It has no file size limits, so there should be no problems.
flv
not much a few MB maybe
divx player can open that extension, or download ultra mpeg converter to convert the flv file into a more common mpeg, mpg, mp4, avi, etc etc