I came across this program:

TubeRobo:
http://www.tuberobo.com/

It's free. You just need to put up a link to them to download it.

It says it automates many YouTube tasks, such as commenting, inviting friends, etc.

I downloaded it and started it up, but haven't ran it yet. It needed netframework 3.5, which took my PC a long time to install/reboot.

It also doesn't have any directions/readme at this point in time, so you'll need to figure things out for yourself.

Looking at it, it seems like it could be good for some aggressive YouTube marketers.