I remember this one animation video that is great to watch... it was on newgrounds for about three years (more or less) but no one has made a conversion of it onto youtube or google video, or any other videos online...

Here's my question (in a two part)...

What is the best way to convert videoes such from newgrounds into a format to say youtube?

Also are we allowed to sumbit videos that we converted? An example: While I converted video and posted it on youtube, I'm not the one who actually created the video... Will I get in trouble if I were to post this video that is under my youtube account or is it allowed?