If your video is in a QuickTime-readable format, you have a wide range of choices.
If you own Quicktime Pro, you can open the video in Quicktime Player and choose File > Export to do conversion. Select the "iPod" export settings if they are available. If not, choose Quicktime movie and use one of the following configurations. H264 at less than 768kps, 320x240 resolution, 30 frames per second. AAC-LC audio up to 160kps stereo, 48Khz. MPEG-4 at up to 2.5 mbps, 480x480, 30 frames per second. AAC-LC audio up to 160kps stereo, 48Khz.

If you don't have Quicktime Pro or are interested in converting a lot of movies at once, I suggest you take a look at Podner. It has a simple, drag and drop user interface and makes conversion simple and fast. Run it, drag your Quicktime movies into the window and press Start. It's just that simple. Other programs such as ffmpeg and iSquint will do the same thing, but from my experience Podner is the fastest.

Converting Windows Media files and Flash movies can be more tricky. Quicktime Pro has some rudimentary support for flash movies, but the sound rarely works when you export. If you own Flip4Mac, you can open all WMV files in Quicktime and export them to iPod without any trouble. If you don't own either of these, the next best thing is screen capture. That's right: opening a flash animation or WMV file in a web browser and recording the screen as it plays. It's unfortunately rather time consuming. After you've finished recording the audio and video off the screen, you've still got to convert the result into H264 for the iPod (see above). When it comes to capturing video on screen, Snapz Pro X will do the trick. It has a wide variety of options and will record audio output as well.

If you're interested in installing iPod Linux on your iPod, you'd probably be better off looking on the iPod Linux website at http://www.ipodlinux.org/. I've written a tutorial for installing the video-capable build on your iPod, which is availble on my blog: Video Instructions. I'd also like to put in a good word for Jefferey Nelson's Mac OS X iPodLinux installer, which should do everything necessary to get iPod linux on your iPod. Check out his website at http://ipodlinuxinstl.sourceforge.net/. Now, about converting videos. The process is complicated because the iPod linux video player doesn't support compression, and audio/video must be perfectly calibrated for the particular iPod you're using. Correct resolutions and color settings are a must. For information about converting videos to iPod linux, see the video player's page in the iPodLinux wiki over here: http://www.ipodlinux.org/Video_Player. And best of luck! Things have become more streamlined since the video player was first released, and I believe you can now do the necessary conversions in Quicktime with the help of a single terminal utility.

If you've never heard of BitTorrent, you may want to read the introduction to it on BitTorrent.com. BitTorrent allows computer users without access to a high-priced server to share files with others on the internet. Also, unlike conventional server-client setups, BitTorrent downloads accelerate as more and more people become interested in a file. Each user downloading the file helps the others get parts of it, which means high-speed transfers of large files.

In the past few years, BitTorrent has unfortunately been associated with several online piracy lawsuits. Because it allows for the transfer enormous files over the internet at high speed, it has become the weapon of choice for those interested in illegally sharing movies and software. However, BitTorrent continues to be an effective solution for the distribution of legal content as well. Most universities run torrent trackers to help with the distribution of research data and large tasks.

At this point, I'll assume you already have an iPod formatted movie that you'd like to upload. If not, follow the instructions at the top of this page. First things first: download a BitTorrent client. I highly recommend Azureus, as it runs on all computer platforms and is the most full-featured. The instructions in this tutorial are for Azureus users. However, most clients are similar.

1. Launch Azureus and select File > New Torrent. Check the "Use an external Tracker" box and enter the announce url. http://www.gotow.net/ipodvideos/tracker/announce.php
   
   
2. Make sure the "Single File" box is checked, and press Next.
   
   
3. Select the movie file you'd like to upload and press Next again.
   
   
4. Select a save location for the .torrent file and check the "Open the torrent for seeding..." box.
   
   
5. Click Finish. When the save is complete, press the Close button.
   

Notice that your movie is now listed in the bottom section of the Azureus window. The status reads "Seeding..." and an unhappy blue face rests next to the file name.

Before you can begin seeding your torrent (providing it to others to download), you must upload the .torrent file to a tracker. In order for others to find your file, it must be posted on a "tracker". The tracker tells interested users how to reach your computer and manages sharing activity.

1. To upload your file to the iPodVideos tracker, go to the Submit page.
   
   
2. Click the "Choose File" button, and locate your .torrent file.
   
   
3. Enter details about the video, including a title, description and category. These are important, because they allow people to find your file on the site and tell them what it is! A file named "Killzone Trailer" is much more attractive than one named "kz.mov."
   
   
4. Click the submit button, and allow the page to reload. You should see a message reading "This torrent is now being tracked. Thanks!"
   

That's it! If you return to Azureus you should notice that in a few minutes the "Seeds" on the file will read 0 (1) meaning that you are seeding the file and that a connection with the tracker was established. The blue face will remain there until someone requests the file.