I just bought one of these to experiment with:
http://www.marvell.com/products/embedded_processors/developer/kirkwood/sheevaplug.jsp
It is basically a tiny linux box with 1.2Ghz processor, with a gigabit
ethernet and USB 2.0 port (
http://nozama.typepad.com/.a/6a00e54ed05fc288330112790d732928a4-800wi ).
Installing packages and software is as easy as normal apt-get procedure,
no custom-compiling needed. You are limited by what little free space is
left on the filesystem, but you can augment that via USB storage.
My first tests with this device will be attaching an HD USB camera and
using mjpeg-streamer to turn it into a cheap network camera. I'd also
like to see if I can attach a small USB hub and run both the camera as
well as a USB ethernet adapter, thus creating a cheap wireless network
camera/device.
If anyone is interested I will post more info when I receive it, and
report on how my testing goes.
-Charles