I’ve been playing around with the public domain films at The Internet Archive. The movies in this collection are generally old industrial films, newsreels, promotional films, and amateur movies, some from as early as 1917. There’s a ton of old WWII and Cold War footage. The quality varies, of course, but much of it is very good, and very interesting to an armchair historian like me.
If you just want to watch old short films, the streaming RealAudio and downloadable Divx files are fine.
If you’re wanting to make your own videos using this footage–one could very easily make corny war movies using this stuff–I recommend using the MPEG-2 files rather than the Divx files. MPEG-2 is a less-lossy format than Divx, plus the files are higher resolution. They’re also about 10x larger, but worth the extra trouble if quality is important to you.
Adobe Premiere won’t allow you to do anything with the large MPEG-2 files out of the box, but don’t let that stop you. I found a freeware MPEG-2 codec. I have no idea how long this link will be good, but give this link a shot. Gatermann warned me about doing a Google search on that specific filename–it brings up some pretty disturbing content. Try searching on things like MPEG2, Win32, and codec, rather than the specific filename.
The MPEG-2 files don’t play back well on your computer because they’re interlaced, but they’re beautiful in Premiere and on a composite monitor.
Another hint for using this archive: Don’t download the files with your browser. FTP into ftp.archive.org. A separate FTP client will download the files much more quickly than your Web browser. Make sure you’re using binary mode. You can find a free GUI FTP client here if you need one.