I connected my WIZ550io to the Arduino R3 by hard wiring:
I made the changes in the Ethernet library for Arduino 1.0.5 as given on the Wiznet instruction page.
I can ping the WIZ550io from a Linux (Debian) Network tools screen through an ethernet switch (small dedicated network).
When I try to get a Webserver Sketch running on the Uno R3, it compiles and loads. When I send an ethernet address (22.214.171.124) to the Uno from the Linux PC (this is the address that pings from Linux) I get a message saying that “192.168.1.2 refused the connection.”