This is the current simplest method to having any youtube video subtitles for free and you don't need any skills at all to do it. In fact they do everything for you.
Now I said "Current" not only because I'm sure that someday there will be even easier methods then this. But because I'm not sure how long they'll offer this service for free. So you might want to jump on it while you can.
All you do is go to their site. Fallow their directions to have a youtube video subtitled for you (Must be under 5 minutes long). Then with in a couple of days they'll send you an Email letting you know that you're video has been subtitled. Just to show you that this really does work. Here's a video they subtitles for me and it only took one day.
Oversteam.net is a site that's similar to youtube videos but all their video's have subtitels. The site includes a subtitle creator tool that allows you to easily create subtitles to your videos. The subtitle creator tool is very easy to use once you get the hand of it. It'll add the subtitles vidoe to their site but below I'll show you how to add the subtitles to youtube.com as well. So if you have a video on youtube you can use overstream.net subtitle creator tool to create your subtitles then add them to your youtube video.
Here's a screen shot of their subtitle creator tool.
Go to their site and you'll be able to learn more about using their creator to create your subtitles. They even have some video tutorials that walk you through the process. It might seem a bit confusing to some of you at first but it's actually very east once you get the hang of it. Even with me being deaf I was able to subtitles a few videos. If I can do it then anyone can. :)
Now let's assume you've gone to overstream.net and created subtitles for one of your videos. The below video will walk you through what to do once you've got the subtitles finished and want to add them to your youtube.com video.