Which Plug Computers are supported by Debian?
There are many different Plug Computer models. The SheevaPlug is the original one and it is well supported. Please check which other models are supported.
How much space do I need to install Debian?
A normal installation of Debian (i.e. base system plus standard components) will take about 400 MB, so a 1 GB USB stick or SD card is enough (even though more is recommended).