Load video to youtube when node save
A combination of following modules would do what you want 


Media



  The Media module provides an extensible framework for managing files
  and multimedia assets, regardless of whether they are hosted on your
  own site or a 3rd party site - it is commonly referred to as a 'file
  browser to the internet'.
  
  Media is a drop-in replacement for the Drupal core upload field with a
  unified User Interface where editors and administrators can upload,
  manage, and reuse files and multimedia assets. Any files uploaded
  before Media was enabled will automatically take advantage of the many
  of the features it comes with.



Media: YouTube



  Media: Youtube integrates with the Media module to make Youtube videos
  available as file entities.
  
  Users can add Youtube videos to their site in a file field or insert
  them into a WYSIWYG area by pasting the video's URL into the media
  browser web tab. Formatter options are available to customize the
  Youtube player's appearance, show the video preview image, and enable
  the Javascript API. The 2x branch is under active development and uses
  the Youtube iframe embed that can serve HTML5 videos to mobile
  devices.



Media Mover 


This is the module that would do what you have asked. I have highlighted the point you have asked


  Media Mover is a set of modules which allows website administrators to
  easily create complex file conversion processes. The core of Media
  Mover is the media_mover_api module which creates a set of rules
  allowing multiple modules to interact with a file. Media Mover can
  take a file emailed to an email account, turn a file attachment into
  an FLV file, create a new node with the file data, and then save the
  file on an external file storage system like Amazon's S3 all at once.
  And that's just the start.
  
  What you can do The core set of Media Mover modules offers lots of
  options for someone manipulating rich media.
  
  
  get attachments from an email account
  get attached files from nodes of a specified type
  get files from previously harvested files
  get files from CCK filefield and imagefield fields
  get files from a FTP server, provide file tokens for user authentication as well
  create a thumbnail from a video file with ffmpeg
  transcode video files into web friendly (and other) formats
  compress a file with zip
  move a file to Amazon's S3 service
  attach file back to node
  save file and related data as a node
  add a file to a CCK filefield or imagefield
  save a file to YouTube