Can any one tell me how to build back links using video submission sites like You tube and so on.
A quite obvious way to do this would be to post (read:spam) your link in the comments sections. You could private message people saying 'come check out this cool site!'. I find that people pm people (me) that commented on a video pertaining to what your website is about. For example, if you have a website about, say, soccer, then find a soccer video of Ronaldo or Messi and pm the people who posted comments saying 'check out this cool soccer site!' (but more interestingly of course).
Of course, this is a purely brute-force way of doing so. I find people who do that to be annoying and I wouldn't visit the site (unless it seemed really interesting). It's irritating and can make people mad...but you'll lose those people anyways. Like I said, bruteforce.