This is probably on of the best tools for recording on-screen activity and turning it into a video that can be shared easily and which can look very professional. It is frequently used by software promoters themselves. It is only a 30 day trial but you could do a lot in that time so I feel it should be included as it is so good.

After that you can use the free open source CamStudio opposite!

CamStudio is able to record all screen and audio activity on your computer and create industry-standard AVI video files and using its built-in SWF Producer can turn those AVIs into lean, mean, bandwidth-friendly Streaming Flash videos (SWFs)

Here are just a few ways you can use this software:

You can use it to create demonstration videos for any software program
Or how about creating a set of videos answering your most frequently asked questions?
You can create video tutorials for school or college class
You can use it to record a recurring problem with your computer so you can show technical support people
You can use it to create video-based information products you can sell
You can even use it to record new tricks and techniques you discover on your favourite software program, before you forget them