ScreenSteps will let you take screenshots, in fact you can even take them with a short delay. In addition, it can interact with other screen captors like Gadwin PrintScreen.
It's very intuitive, you only have to add screenshots and write some notes on them. They'll be featured like those old photographs taken with a Polaroid.
Once you'll have taken all screenshots and written all notes, you'll have to change the position of them and decide to export the tutorial as HTML or PDF.
Finally, it also includes a built-in image editor to perform minor changes on screenshots before finishing the tutorial.