Good point Sylvia: what is "easy"? And, the business of creating accounts does open a can of worms and frankly, can be a deterrent, especially for one-off use.
I think "easy" might mean something I can do with my existing skillset (e.g., I don't need to go and learn a whole bunch more). If I do need to know something more, "easy" would involve clear, step by step instructions for accomplishing the task.
One of the tools we looked at in the session was Bubble Joy - I would classify it as easy. It does require a web cam and mic (which may not be easy for some users), but if you have these things, it requires little more than clicking "record'.
I noticed the quality today wasn't as good as other times I've used it, so maybe their servers are slow for some reason.
Here's an example: http://www.bubblejoy.com/card.php?id=kvyu6