Since animated gifs are the weapon of choice in spreading internet memes around the world and aren't going away anytime soon, there's no reason for us PowerPC users to be left out in the cold. There are several applications that make animated gifs on Windows and Intel-only versions of OS X, but finding applications that do the job on PowerPC, particularly making gifs from video clips, is more daunting. Thankfully there are a couple of open source, cross-platform tools that we can combine to grab the video and then export as gifs, namely avidemux and GIMP.
First, download and install avidemux. On Debian, it's available in the deb-multimedia repositories. On OS X, you can download version 2.4.4 which works on Tiger from SourceForge (your choice of QT4 or GTK versions). Then follow the instructions on HOW-TO: Make an animated gif for using avidemux to extract a clip from a video file, specifically using the "A" and "B" buttons and then saving the selection as jpeg images. Hopefully you created a folder for them because it'll output dozens or even hundreds of jpegs.
Next step is to install GIMP if you haven't. On Debian it's in the official repositories, and Tiger and Leopard versions can be downloaded from this site. Then follow the instructions again from the above HOW-TO, using Open As Layers, maybe opening one out of every three or four frames, then do all the cropping and resizing you want, and export as an animated gif.
And for viewing gifs outside a web browser, there's Xee on OS X and GPicView on Linux.
Here's a quick sample I made. Feel free to repurpose: