You can use Real Player (their newest version) to download in video in the net and save it as .FLV. I use it rather use another untrusted softwares. It's kinda cool. I'm not advertising hehehe Code: http://www.real.com/
umm not sure.. zamar usually work on most youtube video... but dont know about the size.. you can convert videos on zamar.. but i rather just get avi converter if your converting videos only not downloading..
If you want bigger size, try downloading Real. Well of course Real is also useful when you download .RMV and .RMVB formats.