I don't usually recommend software unless I am asked, but I came across something that was too good not to share. I had taken a video while biking down a road here at the cottage and was very disappointed in the result with all the shaking and jittering. I went looking for some way to de-jitter and found a free plugin for VirtualDub. The plugin is called Deshaker and was written by Gunnar Thalin. If you have any video that needs to be "unshaken" I strongly suggest you have a look.