The Arduino Ethernet board apparently has a way of connecting to the
W5100 interrupt on pin 2 - according to the docs, "when bridged".
Does anyone know how you "bridge" the pin - the circuit layout just
leaved the W5100 interrupt line dangling in mid air.
In the upper left hand corner, next to the S in shield, you will see two solder points with one trace leading to pin 2. Solder these two points together to bridge the W5100 to pin 2.
Sorry, I missed the "board" part and just assumed shield.
Concerning the Ethernet board, there doesn't appear to be a simple way to do this. Have a look at Arduino Forum for a recent discussion on the same issue.