The screenshot app you will need you're phone rooted.
The second option mentioned I think is this method. Only problem is you'll need to be next to a computer to take screenshots.
It takes a few minutes to set up but looks simple to take screenshots once it's all set up and you've take that first one.
The instructions are here
How to take screenshots of your Android based phone from Windows - Simple Help
(Personally I've not tried the second option, as my phone doesn't arrive until tomorrow. I'm sure it'll be a priority for me though. Shame that there isn't any good none rooted screenshot apps on the market yet. Hope that changes soon)