It says "Instant Screencasts for Twitter" but it looks like it can do a whole load more. Brilliant little application that records your steps through applications + your voiceover or whatver noise you care to add and puts them in a nice little video that, as they say on the site, "even plays on an iPhones"! That's my exclamation mark as I had to chuckle at that.

I love this tool. Nice intro on the site explains that you can also embed the video in your web pages, send to YouTube as well, very simply. Must add one here...