Here is a pdf with the most useful commands
http://www.nettech.in/course/Basic%20Commands.pdf

I was hoping to be abe to boot to different flavours of linux but as the img files negate this possibilty the low cost of sd cards really makes this point moot i think. It is nice and easy to swap a card out to start Debian one time then Arch the next so i will be using that method when my new shiny...

I have been using puppy on a usb for years when i am working on fixing computers as it is small and fast and gives me access to the file system easily. I would be very interested inlooking at puppy on my soon to arrive Pi! Looking forward to it.