code: public void setUserDefinedURL(String desc, String url)
  	{
  		if (allow(ID3V2))
  		{
  			id3v2.setUserDefinedURLFrame(desc, url);
  		}
  	}
docs: Add a link to this mp3 (id3v2 only).  This includes a description of
  the url and the url itself.
  
  @param desc a description of the url
  @param url the url itself