Thanks liudr, I started it but Jon's done the hard work.
Looking at the ethernet shield schematics we have
A0 -> WP - write protect
A1 -> DETECT - probably used to detect if the card is inserted
D2 -> SS
D10 -> PD2
D11 -> MOSI
D12 -> SD_CS/MISO
D13 -> SCK
Whether that matches the site I don't know (too late to check now) but it looks like the Arduino site is wrong. There's two revisions of this board, maybe the text refers to the earlier version.
Rob