Umm... for a scenario type storyboarding it's okay. Especially since it's free which is always a personal favorite of mine.

This is okay as far as it goes. It just doesn't go anywhere near far enough. Storyboard Artist, and several others are pricey - but they do it just as well.

PowerPoint has an awesome Storyboard plugin that, unfortunately is only available to Microsoft Developers with the top of the line package of Visual Studio (in all fairness they only meant for it to be used to tell software development and product scenarios - its free to anyone with that software as scenario storyboarding is a part of the software development process with them) -- But of all the storyboarding tools I've ever used ... it is the easiest, fastest and produced the best results -- hands down.

Balsamiq is well known and does a good job also, there's a couple of followers of it that are now out there as well - and their free also.

Storyboard Artist - if you have the cash is a staple of smallish film productions. Springboard is a very good alternative and aside from the library StoryboardThat has, has all of it's features and more and is pretty cheap.

Celtx, used to be really good but I haven't tried it in a while. They went all "mobile" for a while there and kinda lost me as a customer. But they used to have a really good product - both for writing comics and also for storyboarding them (and film/theatre).

Adobe Story 'can' work as a storyboarding tool... I just haven't played with it myself.

Most real storyboards are done still by hand or digitally in Photoshop or similar. A lot of people just scribble on a pad, scan it and drop them into a template - and done. Looks better and you can always digitally rework the stick figure sketches into something nicer as you go.