I have needed to make online demonstration videos recently. The strategy I have come up with for this, which seems to avoid too much rework, and yields a reasonable quality video is:
1. Use GotoMeeting in 'record' mode to capture the video
2. GotoMeeting uses a proprietary capture format - but this can be converted to a normal .wmv file with:
g2mtranscoder.exe source=c:\video.wmv
3. View the video and record a voice over with 'Audacity' saving the audio in mp3 format
4. Merge the audio and video with:
ffmpeg -i video.wmv -i audio.mp3 -acodec copy -vcodec copy -map 0:1 -map 1:0 output.wmv
In the final step the -map options may need to be adjusted, depending on the way the video file is created by the GotoMeeting session
I try to make the recording in a single take, to avoid large scale editing, which is tedious. This overall strategy results in videos which are high enough in quality for the text in dialog boxes to be visible (which is important in training videos) but with manageable file sizes.