As an addendum to my previous post, there are now two free options for getting your files compressed into the aforementioned WebM container (and both work on Mac and PC). In terms of viewing the final product on a website, someone with a greater degree of webpage/server knowledge will have to take that one up. For the time being though, if you download the most recent version of VLC, you can play the files locally (with varying levels of success).
The first, and I think more successful, of the two options is the Miro Video Converter (www.mirovideoconverter.com). It is available for both Mac and PC, though it looks like it might have been intended as a Mac application first. MVC is free, open-source, and is on version 2.2. An added bonus is that the application is very simple to use and will perform a number of 'hands-off' conversions (MP4, Theora, WebM) as well as conversions designed for portable/mobile devices (Android, PSP, iPhone, iPod, iPad). The GUI is extremely simple, using a drag & drop + drop-down menu design. The actual WebM conversion left me less than impressed in most areas other than size. I was able to take a 2.1 GB uncompressed HD video stream down to a 2.8 MB .webm file. The motion estimation was decent, though with lots of movement the file quickly pixellated. The color was also slightly dull as compared to a similarly compressed H.264 file (2100 kbps, Medium Quality, Automatic Keyframes), with colors in the red spectrum being particularly muted (though as Joe noticed in an older post, H.264 tends to boost colors, so maybe this is the effect that I was experiencing when comparing side by side).
The second is Sorenson Squish (www.sorensonmedia.com/video-content), which uses a web-based Java app in tandem with your computer's processing power to compress files into a number of different codecs/containers, of which WebM is the only one allowed in the free trial. The GUI is similarly accessible, and anyone who is able to use in-browser uploading systems like those employed by Flickr, YouTube, or even blogs will have no trouble using Sorenson Squish. The Java applet runs in most browsers (not Minefield, but regular Firefox, IE, Chrome, and Safari work fine), compresses the source file on your machine, and uploads only the compressed file, which takes much less time (and allows you to use a higher quality source file) than a service like Zamzar. You can choose to save a copy of the file on your local machine as well. The qualms with the resulting file are similar to MVC, but moreso, due to the fact that one ends up with files that run at around 425 kbps, and as a result look very poor. You also have to register for an account to use Squish, though doing so gives you 1 GB of online storage and lets you see what your videos look like when played inside a browser. I believe a paid upgrade is necessary to unlock some of the fine tuning features.
Both of these applications, as I note in the earlier post, suffer from too little user-control. I also think that the VP8 video codec is not quite as robust as Google/On2 made it out to be. I still think H.264 looks better, though VP8 is still in its infancy and very well may, due to its open code, surpass H.264's longstanding ascendancy in the world of video codecs. I can see this occurring especially in ratios of quality:size. The Vorbis audio codec was also intermittent in its functionality, a few times putting files out that only had a loud hiss for an audio track. In any case, it is still exciting to see new technologies embracing WebM, and I am sure that the manifestation/practical side of the equation will improve, especially as the demand for files packaged in WebM increases.