If you happen to have a 2GB SD card and you are thinking about trying the Angstrom demo that Koen has created but are scared of all the partitioning, formatting, and copying instructions you are finding on the web, then I hope I'm about to share some joy with you.
Ubuntu now distributes a tool for writing images onto USB sticks and SD cards for the purpose of evaluating Ubuntu. For those of us who use Linux on a daily basis, it serves largely the same purpose as the 'dd' command, but it runs in Windows and Mac OS X as well and has a GUI to help prompt you along the way. You can get the tool from:
Additionally, Koen, a maintainer for the Angstrom Distribution, has produced an image under his demo directory at:
You'll still need a tool to uncompress the image (which is Bzip2 compressed), but the rest should be mostly self-explanatory. Hopefully other distributions will follow and more SD images will be available soon!