Although there are a few good video formats that almost everyone should be able to play, it seems the only way to guarantee that someone will be able to view your video over the Internet is to use some flash-video based service, such as YouTube or Google Video.  The problem is that these services have a long lead time, slow upload time, and poor quality.  You can do better by rolling your own. The basic components are as follows:

1.  Transcoder (such as ffmpeg)
2. Flash wrapper (such as http://blog.deconcept.com/swfobject/)

The approach is to do the following:

1.  Transcode your video to dv format (it may be possible to go directly to FLV, but with ffmpeg for Mac OS X, this is the only method I found that works)
2. Transcode your dv to flv – if you are going from 16:9 you can set ffmpeg to output at 640×352 to get a good equivalent. 
3. Edit the .html file that comes with the Flash Wrapper so that it points to your video.  Also change the resolution to 640×352
4. Upload the swfobject.js, flvplayer.swf, along with your .html and .flv files

That should do it!  Here’s an example of what I produced from this effort: http://carson.oakenweld.com/leahNature.html